RU2808649C2 - Paper straw - Google Patents

Abstract

FIELD: drinking straws.

SUBSTANCE: bendable drinking straw (10), made of paper, extending along the longitudinal axis (Z), including a flexible shaped part (13) designed to bend one above the other two adjacent parts (14, 15) of the straw (10). The flexible shaped part (13) is represented by a plurality of depressions (16), located sequentially along the longitudinal axis (Z), and each is made on a limited peripheral part of the circular cross-section of the straw (10).

EFFECT: provides a bendable paper straw that can completely replace bendable plastic straws, and also a paper straw that can achieve such high bending angles without thereby compromising its structural mechanical characteristics as well as its sealing characteristics with respect to liquids.

15 cl, 16 dwg

Description

TECHNICAL FIELD

The embodiments of the invention described below relate to a bendable drinking straw made of paper and a corresponding method for making the same.

PREREQUISITES FOR CREATION OF THE INVENTION

Plastic drinking straws are known, commonly used in the food industry for drinking (sipping) beverages from containers such as glasses, bottles, cardboard packaging, for example, in the form of a parallelepiped, also known as "brick" (Tetra-brick packaging).

It is also known that some types of straws are bendable straws having a flexible shaped portion that allows the end portion of the straw to bend on itself, generally at an angle of 180°. Typically this shape is a corrugated type shape having a sequence of annular ridges and tapered portions that are concentric and coaxial in the longitudinal extent of the straw, such as grooves, notches, or thicknesses that allow bending.

In this regard, in particular, it is known that straws are often packaged on the front side of the container. In these cases, it is necessary to reach high-multiplicity angles, mostly 180°, while keeping the straw size small so that it does not protrude beyond the main part of the container.

It is also known that the plastic from which the straws in question are made, due to the technological properties inherent in the plastic material itself, makes it possible to achieve the design characteristics required for straws with relative ease, and in particular with the help of the flexible shaped part of the straw.

However, plastic straws also have many disadvantages, including environmental pollution and poor biodegradability of plastic.

For this reason, an alternative to plastic straws is the more environmentally sustainable paper straws.

There are known methods for manufacturing tubular bodies from paper or cardboard based on the spiral winding of one or more paper strips or threads (thread winding). This manufacturing technology can be used to produce cylindrical bodies by spirally winding paper strips or threads under tension around a rotating element, such as a mandrel, using one or more intermediate layers of adhesive (gumming operation), to provide structural stability, as well as at least at least partially waterproof. For example, patent document EP-B-1.631.425 describes a device for producing tubular bodies from strips that are helically wound around a mandrel.

Another manufacturing technique that can be used consists of winding two sheets of paper around a longitudinal axis, placing them along the edges where they are glued.

For this reason, for the production of foldable paper straws, the use of a bendable part, bending at an angle of 180°, represents a new possibility, depending on the special properties of the material used, since the paper has significant mechanical resistance to the processes possibly used.

For example, from patent document US-A-2,985,077 and US-B-9,974,403, bendable drinking straws made of paper are known, in which the flexible molded part is a sequence of circular annular tapered parts, each of which allows angular deviations through a certain interval.

However, one disadvantage of these known solutions is that, due to the large bend radius, these solutions do not allow the end portion of the straw itself to be bent at an angle of 180° until a very long flexible portion is provided, and thus they do not correspond to the practical and industrial needs considered, for example for the production of small drinking straws, for example straws for brick-type containers.

Therefore, there is a need for an improved straw that can overcome at least one of the disadvantages of the prior art.

Specifically, one of the objects of the present invention is to provide a foldable paper straw that allows for the greatest possible bending angles, preferably also at 180°, while maintaining a short flexible body length.

It is also an object of the present invention to provide a foldable paper straw that can achieve such extreme bending angles without thereby compromising its structural mechanical properties as well as its liquid sealing properties.

Another object of the present invention is to provide bendable paper straws that can completely replace bendable plastic straws.

Another object of the present invention is to provide a method that allows foldable paper straws to be produced in a simple and efficient manner.

Applicant has made, tested and implemented the present invention in order to overcome the disadvantages of the prior art and achieve these and other objects and advantages.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is set forth and characterized by the independent claims. Subordinate claims describe other features of the present invention or embodiments of the invention.

According to the above-mentioned objects, the present invention relates to a bendable drinking straw made of paper, having a circular cross-section and extending along a longitudinal axis, including a flexible shaped portion.

The flexible molding is designed to allow two adjacent straw portions to bend, one over the other.

The flexible shaped part is formed by a plurality of depressions located sequentially and with an angular displacement along the longitudinal axis and each is made transverse to the longitudinal axis on a limited peripheral part of the circular cross-section of the straw.

In some embodiments, the dimples have an angular offset relative to longitudinally adjacent dimples.

According to some embodiments of the invention, the flexible molding consists of at least one group of dimples that includes a first pair of dimples formed on a limited peripheral portion of the straw and aligned with each other in a direction parallel to the longitudinal axis, and a second pair of dimples located between and with angular displacement to the two depressions of the first pair of depressions.

According to one aspect of the present invention, the plurality of recesses consists of groups of recesses located along the longitudinal direction of the flexible fitting and at an angular offset with respect to each other.

Preferably, the configuration, depth and number of dimples may determine the direction of folding and the maximum amount of possible angular deflection that can be achieved between portions of the straw adjacent to the flexible molding.

Advantageously, it is thus possible to achieve large angular deviations between two adjacent parts of the straw while maintaining the longitudinal direction of the flexible molded part.

Embodiments include one or more depressions formed on a peripheral portion defined by one side of the annular section of the straw, which may have a preferred folding direction.

The present invention also relates to a method for producing a bendable drinking straw made of paper with a circular cross-section that is directed along the longitudinal axis.

The method involves making a number of depressions along a cylindrical tubular body made of paper, located sequentially and with angular displacement along the longitudinal axis.

Each depression is made transversely to the longitudinal axis on a limited peripheral part of the circular section of the cylindrical tubular body made of paper, outlining a flexible shaped part configured to bend, one above the other, two adjacent parts of the straw.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of certain embodiments of the invention, given by way of non-limiting example with reference to the accompanying drawings, in which:

- in fig. 1a and 1b schematically illustrate a straw according to embodiments of the present invention;

- in fig. 1c and 1d are schematic representations of a straw according to embodiments of the present invention, along section AA' of FIG. 1a and 1b;

- in fig. 2 shows a straw in a bendable configuration, according to embodiments of the present invention;

- in fig. 3 is a schematic diagram of a straw according to embodiments of the present invention;

- in fig. 4 is a schematic diagram of a straw according to embodiments of the present invention;

- in fig. 5 is a schematic sectional view according to embodiments of the present invention;

- in fig. 6 is a schematic sectional view according to embodiments of the present invention;

- in fig. 7a and 7b are schematic sectional views according to embodiments of the present invention;

- in fig. 7c and 7d are schematic representations of a portion of a straw according to embodiments of the present invention, along a section BB' of FIG. 7a and 7b;

- in fig. 7e is a schematic view of a portion of a straw according to embodiments of the present invention, along a section CC' of FIG. 7a;

- in fig. 7f is a schematic view of a portion of a straw according to embodiments of the present invention, along a section DD' of FIG. 7b;

- in fig. 8 is a schematic diagram of a portion of a straw according to embodiments of the present invention.

For better clarity, the same positions have been used, where possible, to indicate identical common elements in the drawings. It should be understood that elements and characteristics of one embodiment of the invention may be conveniently inserted into other embodiments of the invention without further explanation.

DETAILED DESCRIPTION OF SOME OPTIONS FOR IMPLEMENTING THE INVENTION

The inventors will not discuss in detail the various embodiments of the invention, of which one or more examples are shown in the accompanying drawings. Each example is provided with illustrative material of the invention and is not intended to be limiting. For example, features shown or described as part of one embodiment of the invention may be applied to, or in connection with, other embodiments to produce another embodiment of the invention. It is understood that the present invention is intended to include all such modifications and variations.

Before describing these embodiments of the invention, the authors should also clarify that the present description is not limited in its application to the design details and arrangement of components, as described in the following description using the accompanying drawings. Other embodiments of the invention may be described herein and may be prepared or performed by various other methods. The inventors should also clarify that the phraseology and terminology used herein are for descriptive purposes only and should not be considered limiting.

Embodiments of the invention, described with the help of the accompanying drawings, relate to a bendable drinking straw 10 made of paper with a circular cross-section and extending along the longitudinal axis Z.

The straw 10 consists of a flexible shaped portion 13 that is made to bend two adjacent portions 14, 15 of the straw 10 one above the other and preferably at an angle of about 180°.

The flexible molded part 13 has a plurality of depressions 16 arranged in series and with angular displacement along the longitudinal axis Z, and each is made transverse to the longitudinal axis Z on a limited peripheral part of the circular cross-section of the straw 10.

With reference, for example, to FIG. 1a, 1b, 7a, 7b, the straw 10 may comprise one hollow tubular body, elongated and substantially cylindrical in shape, wound around a longitudinal axis Z.

The straw 10 thus has two ends, which for illustrative purposes only may be designated an upper end 12 and a lower end 11.

In particular, the terms "upper" and "lower" are not to be understood herein in a limiting sense with respect to the functionality and/or configuration of the straw 10, which can be used in the usual and customary manner as products of this type.

In some embodiments of the present invention, the straw 10 is made of paper material, and in particular, it can be made in the form of a plurality of overlapping layers of paper, or strips, such as spirally or longitudinally.

In some embodiments of the present invention, at least one of the overlapping layers or strips may be adhesive applied, that is, gummed. The adhesive provides structural and mechanical adhesion to the straw 10, as well as substantially water resistance, at least for the required period of time.

In some embodiments, the straw 10 may have an outer diameter in the range between 2 and 20 mm, preferably in the range between 4 and 10 mm.

In some embodiments, the straw 10 may have a thickness in the range between 0 and 0.5 mm.

In some embodiments, the straw 10 may have a length in the range between 100 and 400 mm.

The intermediate part of the longitudinal extension of the straw 10, with a length variable in a range according to requirements, has a flexible shaped part 13.

The flexible fitting 13 has two adjacent parts 14, 15, of which, for example, a lower part 14 is substantially rigid, which extends between the flexible fitting 13 and the lower end 11, and a substantially rigid upper part 15, which extends between the fitting 13 and the lower end 11. upper end 12.

In some embodiments of the invention, the flexible fitting 13 may be configured to bend the lower portion 14 and the upper portion 15 one above the other, preferably at an angle of 180°, so that an axis of rotation is provided in the flexible fitting 13.

The straw 10 may thus have an elongated configuration, as illustrated by the examples in FIGS. 1a, 1b, 3, 4, 7a, 7b, where the top 15 and the bottom 14 are aligned with each other, that is, they form an angle of 180°, and corner configurations, in which the top 15 and the bottom 14 form angles, which are subject to change.

In the embodiments of the invention shown in FIGS. 2, mainly for example in the case of the straw 10 used for brick containers, the lower part 14 and the upper part 15 can be subjected to rotation with a return angular deflection even at an angle of 180° in all directions.

In these cases, the straw 10 may also have a bendable configuration such that the angle formed between the bottom portion 14 and the top portion 15 is substantially 0°.

In some embodiments of the present invention, the feature that allows the flexible molded portion 13 to serve as an axis of rotation between the lower portion 14 and the upper portion 15 is associated with the presence of a plurality of recesses 16.

In some embodiments, the dimples 16 may be designed as a deformation of the surface of the straw 10, resulting in a lower level relative to the average surface level in the surrounding area.

In some embodiments, the dimples 16 may be formed as a result of pressure exerted by suitable contrasting means, such as, for example, pins, edges, teeth, protrusions of various shapes and sizes.

The structure of the dimples 16 may determine the direction of folding between the lower portion 14 and the upper portion 15 of the straw 10.

For example, a dimple 16 provided on a peripheral portion defined by one side of the circular cross-section of the straw 10 may allow the straw 10 to bend in a bending direction determined by the side where the dimple 16 is applied.

In another example, the presence of two opposing dimples 16 may allow the straw 10 to bend in two bending directions determined by the sides where the dimples 16 are formed.

In addition, the depth and number of dimples 16 may determine the maximum amount of possible angular deflection that can be achieved between the bottom 14 and the top 15 of the straw 10.

In particular, it is possible to increase the value of the angular deviation associated with each depression 16 as its depth increases.

In addition, the fact that the depressions 16 have an angular offset with respect to each other allows the paper material to be weakened in accordance with the flexible molding 13, preventing the occurrence of break points, excessive deformation edges, allowing them to be folded in a controlled manner.

In the embodiments of the invention described with reference to FIGS. 7a, 7b, 7c, 7d, 7e and 7f, the flexible molding 13 consists of at least one group of dimples 16, which includes a first pair of dimples 16c formed on a limited peripheral portion of the straw 10, aligned with each other in a direction parallel to the longitudinal axis Z, and a second pair of depressions 16d, placed between two depressions of the first pair of depressions 16c and with an angular offset relative to them.

The two depressions of the first pair of depressions 16c may be located on the same side of the straw 10 with respect to the longitudinal Z axis.

The two depressions of the second pair of depressions 16d may be opposite and aligned in a direction substantially orthogonal to the longitudinal Z axis.

In some embodiments, the two dimples of the second pair of dimples 16d are substantially offset at an angle of 90° with respect to the first pair of dimples 16c.

In the embodiments of the invention described with reference to FIGS. 7a, 7b, 7e and 7f, since one side of the straw 10 is defined by the position of one of the depressions of the first pair of depressions 16c with respect to the longitudinal axis Z, the other depressions of the first pair of depressions 16c are located on the same side.

In addition, given that the longitudinal section of the flexible molded portion 13 extends along the longitudinal axis Z and through the first pair of recesses 16c, the two recess lengths of the first pair of recesses 16c are located on the same side of the longitudinal section.

In addition, since the other side of the straw 10 is determined by the position of one of the depressions of the second pair of depressions 16d with respect to the longitudinal Z axis, the remaining depressions of the second pair of depressions 16c are located on the side opposite the other side with respect to the longitudinal Z axis.

In these embodiments, therefore, taking into account a longitudinal section of the flexible molded portion 13 extending along the longitudinal axis Z and through the second pair of recesses 16d, the two recess lengths of the second pair of recesses 16d are located on opposite sides of the longitudinal section.

In these embodiments, the straw 10 may have a preferred fold direction determined by the side on which the first pair of dimples 16c is applied.

Likewise, in the embodiments of the invention described in conjunction with FIGS. 4, two depressions 16 are located on each side of the straw 10, arranged sequentially along the longitudinal axis Z, with an angular offset with respect to each other at an angle of approximately 180°, and each is located on the peripheral portion limited by one side of the circular cross-section of the straw 10.

In these embodiments, the straw 10 can be bent in two bending directions defined by the two sides on which the dimples 16 are applied.

In some embodiments of the invention, the plurality of recesses 16 are configured as groups of recesses 16 located along the longitudinal direction of the flexible molded portion 13, as illustrated by examples in FIGS. 1a, 1b, 2, 3, 4.

In some embodiments, the groups of dimples 16 have an angular offset relative to the longitudinally adjacent groups of dimples 16.

It will be appreciated that the groups of dimples 16 may include both dimples 16 formed on the peripheral portion defined by one side of the circular cross-section of the straw 10, and also pairs of opposing dimples 16 are schematically illustrated in FIG. 7a, 7b, 7e and 7f.

These embodiments of the invention may have a preferred folding direction defined by dimples 16 formed on one side.

Applicant confirms that high angular deflection values, such as 180°, can be achieved by using a minimum of two sets of dimples along the longitudinal direction of the flexible fitting 13, preferably three or four sets of dimples 16.

Advantageously, since the depressions 16 are designed as surface deformations rather than thickness indentations, they can have varying depths relative to the average surface level of the straw 10, according to the diameter of the straw 10, thus not compromising the seal of the straw 10 itself for leakage of liquids.

One advantage of the present invention over prior art foldable paper straws, therefore, is that it is possible to achieve high angular deflection values between the bottom portion 14 and the top portion 15 while increasing the depth of the depressions 16 and maintaining their number, and thus maintaining longitudinal direction of the flexible fitting 13.

This advantage is particularly important in cases where the straw 10 must comply with predetermined parameters in terms of shape, size and length, such as in the case of straws for brick containers.

In the embodiments of the invention described with reference to FIGS. 1a, 1b, 1c, 1d, opposite pairs of depressions 16 are used, with an angular displacement at an angle of 90° with respect to the longitudinal adjacent pairs of depressions 16.

In particular, in those views shown in FIGS. 1c, 1d, a pair of dimples 16a can be seen in the axial surface with an angular offset of 90° with respect to the longitudinally adjacent pair of dimples 16b.

In other embodiments of the invention described by way of example with reference to FIGS. 5, groups of dimples 16 are groups of three dimples 16, for example, located at angular intervals of approximately 120° along the periphery of the straw 10.

In these embodiments, the groups of three dimples 16a may have an angular offset of about 60° with respect to the longitudinally adjacent groups of three dimples 16b.

Other embodiments of the invention are possible, described as examples with reference to FIGS. 6, in which the dimple arrays 16 are arrays of four dimples, for example, applied at angular intervals of approximately 90° along the periphery of the straw 10.

In these embodiments, the groups of four dimples 16a may have an angular offset of approximately 45° with respect to the longitudinally adjacent groups of dimples 16b.

The depressions 16 can have different shapes and sizes, so that in a stepped fold, the interaction between the lengths of the depressions 16, located in succession and having an angular displacement along the longitudinal axis Z, creates bending tracks, or patterns, along which the flexible molded part 13 bends, allowing bending and/or mutual rotation of the lower part 14 and the upper part 15.

In the embodiments of the invention described with reference to FIGS. 1a, 1b, 2, each depression 16 has a straight extension formed on the peripheral portion of the straw 10, perpendicular to the longitudinal Z axis.

Other embodiments of the invention described with reference to FIGS. 3, each depression is provided to have a straight extension formed on the peripheral portion of the straw 10, inclined with respect to the longitudinal axis Z, for example, with an inclination angle of between approximately 30° and 60°.

In these embodiments of the invention, the interaction between the inclined extents of the depressions 16, located with an angular offset, can form bending tracks, or patterns of a helical type.

Other embodiments of the invention may also provide recesses 16 with a curved extent, such as an arcuate or wedge-shaped one.

It will be appreciated that the number, location, size and extent of the depressions 16 can be changed as needed, for example depending on the size of the straw 10, the required bend angle and/or depending on the dimensions required for the straw 10.

In particular, straws 10 with a larger circumference may have more dimples 16 and/or larger dimples 16.

The present invention also relates to a method for producing bendable drinking straws 10 made of paper with a circular cross-section and an extension along the longitudinal axis Z.

The method according to the present invention includes the steps:

- the presence of paper material in layers or strips;

- winding layers or strips of paper material, for example, around a mandrel, so as to obtain a cylindrical tubular body of paper;

- manufacturing along the cylindrical tubular paper body a plurality of depressions 16, located sequentially and with angular displacement along the longitudinal axis Z, and each in a transverse direction to the longitudinal axis Z, on a limited peripheral part of the circular section of the cylindrical tubular paper body; thus, the plurality of depressions form a flexible shaped part 13, configured to bend one over the other two adjacent parts 14, 15 of the straw 10;

- cutting the hollow tubular body so as to obtain a straw 10, that is, an upper end 12, a lower end 11, an upper part 15, a substantially rigid lower part 14, a substantially rigid and flexible shaped part 13, inserted between the upper part 15 and a lower portion 14 and surrounded by an area affected by the depressions 16.

In some embodiments of the invention, the method also includes manufacturing along the cylindrical tubular paper body at least one group of dimples 16, which consists of a first pair of dimples 16c formed on a limited peripheral portion of the straw 10 and aligned with each other in a direction parallel to longitudinal axis Z, and a second pair of depressions 16d located between and with an angular displacement relative to the two depressions of the first pair 16c.

In some embodiments, the method also includes making two dimples of the first pair of dimples 16c on the same side of the straw 10 with respect to the longitudinal Z axis.

In some embodiments, the method also includes making the two recesses of the second pair of recesses 16d opposite and aligned in a direction substantially orthogonal to the longitudinal Z axis.

In some embodiments, the method also includes making the two recesses of the second pair of recesses 16d offset at substantially a 90° angle with respect to the first pair of recesses 16a.

In some embodiments of the invention, winding layers or strips of paper material can be accomplished using thread winding techniques and devices.

In some embodiments of the invention, sheets of paper layers may be wound around the longitudinal axis Z, overlapping each other and gluing the edges together.

In some embodiments, three layers or strips of paper material may be used, at least one of which, for example, an intermediate layer or strip, is impregnated with an adhesive suitable to provide cohesion to the layers or strips and adhere tightly to the straw 10.

In some embodiments, the intermediate layer of paper material may be impregnated with adhesive only on the outer surface to prevent the adhesive from contacting liquids passing through the straw 10.

It will be appreciated that modifications and/or additions to parts or steps may be applied to the straw 10 or to the method as described above without departing from the scope and scope of the present invention.

It will also be apparent that while the present invention has been described with reference to certain specific examples, one skilled in the art will, of course, be able to prepare many other equivalent straw shapes having the characteristics as described below in the claims, thus while remaining within the scope of protection of the invention described with their help.

In the following claims, the sole purpose of the parenthetical references is to aid reading and should not be considered as limiting the scope of protection claimed in the claims that characterize the specific embodiment of the inventive idea.

Claims (15)

1. A bendable drinking straw (10), made of paper, with a circular cross-section and length along the longitudinal axis (Z), including a flexible shaped part (13), made with the ability to bend, one above the other, two adjacent parts (14, 15) straws (10), said flexible shaped part (13) consisting of a plurality of depressions (16) arranged sequentially along the longitudinal axis (Z), wherein the straw is characterized in that the depressions (16) consist of groups of depressions (16) , located along the longitudinal extent of the flexible shaped part (13) and with an angular displacement relative to each other along the longitudinal axis (Z), and the fact that each depression (16) is made transverse to the longitudinal axis (Z) on a limited peripheral part of the circular section straws (10). 2. The straw (10) according to claim 1, wherein the flexible molded part (13) consists of at least one group of dimples (16) which includes a first pair of dimples (16c) formed on a limited peripheral portion of the straw (10) and aligned with each other in a direction parallel to the longitudinal axis (Z), and a second pair of depressions (16d) located between and angularly offset with respect to the two depressions of the first pair of depressions (16c). 3. The straw (10) according to claim 2, wherein the two depressions of the first pair of depressions (16) are located on the same side of the straw (10) with respect to the longitudinal axis (Z). 4. The straw (10) according to claim 2 or 3, wherein the two depressions of the second pair of depressions (16d) are opposite and aligned in a direction substantially orthogonal to the longitudinal axis (Z). 5. Straw (10) according to any one of paragraphs. 2-4, in which two depressions of said second pair of depressions (16d) are offset at an angle of 90° with respect to the first pair of depressions (16c). 6. The straw (10) according to claim 1, characterized in that it includes opposing pairs of depressions (16), with an angular displacement at an angle of 90° with respect to the longitudinally adjacent pairs of depressions (16). 7. The straw (10) according to claim 1, characterized in that it contains groups of three depressions (16) located at angular intervals at an angle of 120° along the periphery of the straw (10), and with an angular displacement at an angle of 60° with respect to to longitudinal adjacent groups of depressions (16). 8. The straw (10) according to claim 1, characterized in that it contains groups of four depressions (16) located at angular intervals at an angle of 90° around the periphery of the straw (10), and with an angular displacement at an angle of 45° with respect to to the longitudinally adjacent four depressions (16). 9. Straw (10) according to any one of paragraphs. 1-8, characterized in that each depression (16) has a linear extension perpendicular to the longitudinal axis (Z). 10. Straw (10) according to any one of paragraphs. 1-8, characterized in that each depression (16) has a linear extension inclined with respect to the longitudinal axis (Z), in particular at an angle of inclination ranging from 30° to 60°. 11. A method for manufacturing a bendable drinking straw (10) made of paper with a circular cross-section and extending along the longitudinal axis (Z), wherein said method includes manufacturing a plurality of depressions (16) along a cylindrical tubular body made of paper, located sequentially along the longitudinal axis (Z), constituting a flexible shaped part (13) configured to bend one above the other two adjacent parts (14, 15) of the straw (10), wherein the method is characterized in that it also includes manufacturing along said cylindrical body from paper of groups of depressions (16) located along the longitudinal extent of the flexible shaped part (13) and with an angular displacement relative to each other along the longitudinal axis (Z), and the fact that each depression is made transverse to the longitudinal axis (Z) on a limited the peripheral part of the circular cross-section of a cylindrical tubular body made of paper. 12. The method according to claim 11, which also includes manufacturing along the cylindrical tubular paper body at least one group of depressions (16), which contains a first pair of depressions (16c) made on a limited peripheral portion of the straw (10) and aligned with each other in a direction parallel to the longitudinal axis (Z), and a second pair of depressions (16d) located between and angularly offset with respect to the two depressions of the first pair of depressions (16c). 13. The method according to claim 12, which includes making two depressions of said first pair of depressions (16c) on the same side of the straw (10) in relation to the longitudinal axis (Z). 14. Method according to any one of paragraphs. 12 or 13, which includes making two recesses of a second pair of recesses (16d) opposite and aligned in a direction orthogonal to said longitudinal axis (Z). 15. Method according to any one of paragraphs. 12-14, which includes making two recesses of a second pair of recesses (16d) offset at an angle of 90° with respect to said first pair of recesses (16a).

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