GB2579258A

GB2579258A - Bendable paper straw

Info

Publication number: GB2579258A
Application number: GB1905880.9A
Authority: GB
Inventors: Damarell Keith
Original assignee: Havi Global Solutions Europe Ltd
Current assignee: Havi Global Solutions Europe Ltd
Priority date: 2019-04-26
Filing date: 2019-04-26
Publication date: 2020-06-17
Also published as: GB201905880D0

Abstract

A drinking straw 3, comprising a plurality of layers comprising paper, comprises a first straight portion 30, a second straight portion 32 and a bendable portion 34 arranged between the first and second straight portions. The bendable portion is configured to bend to position the first straight portion at an angle relative to the second straight portion. The straw further comprises a thermoplastic layer arranged between the plurality of layers comprising paper. The thermoplastic layer may comprise a water-resistant barrier coating and may extend along the whole length of the straw. The thermoplastic layer may comprise a heat sealable layer that bonds the paper layers without the use of additional adhesive. The paper layers may comprise first and second paper layer, wherein an inner surface of the first paper layer is bonded to an inner surface of the second paper layer. The thermoplastic layer may comprise a styrene free acrylic based coating or a styrene-based coating. The straw may be repulpable, biodegradable and/or recyclable. The straw may be spirally wound and the first and second paper layers may have the same weight. Also disclosed is a method of shaping a straw comprising a plurality of paper-based layers.

Description

Bendable Paper Straw

Field of the Invention

The present invention belongs to the field of drinking straws. In particular, embodiments of the invention relate to repulpable and/or recyclable, bendable straws comprising paper-based materials.

Background

Paper straws are generally made by combining multiple layers of paper via a spiral winding tube process using a water-based glue to adhere the layers together. The papers used to make these straws are generally wet strength papers. Wet strength papers typically contain high levels of wet strength resin additives (e.g. epichlorohydrin resin) that helps maintain cellulose fibre bonding even in high water environments.

Without the wet strength resin, the hydrogen bonds that provide the paper strength in dry conditions, fail when exposed to water. Typical papers contain chemicals known as sizing agents that impart some water resistance (e.g. AKD, ASA, Rosin size) but sizing alone fails to provide enough wet strength integrity for the paper straw to perform adequately. Therefore, wet strength papers are typically used.

There are a wide range of paper straws in terms of size and dimensions. Paper straws vary in diameter, thickness and length but each has similar overall characteristics.

Bendable straws are often produced by a process that compresses one part of the straw to create a concertina style pattern about 30% from one end. This provides some flexibility to the straw, allowing it to bend. Typically paper straws made by this process can only be bent to an angle with a maximum bend angle of 60 to 90 degrees from straight. A plastic straw can be configured to have a similar bend at one end during the extrusion and manufacturing process, for example via embossing. These plastic straws can achieve bend angles of up to 180 degrees from straight by virtue of the elastic properties of plastics. However, there is an increasing public demand for plastics to be replaced with more environmentally friendly alternatives. No known process exists today to allow a paper straw to be bent and to retain an angle of greater than 90 degrees, ideally 180 degrees from straight.

Some deficiencies seen with paper straws are as follows: 1. The paper straw starts to soften immediately on immersion in a liquid. Softening continues until the straw integrity fails. Softening can be delayed via the inclusion of wet strength resin but typically a straw will fail after about 30 minutes.

2. The outer surface of a paper straw normally uses an expensive, extra smooth, wet strength paper so the smoothness can provide "lip comfort' for the consumer. Lip comfort, however, begins to deteriorate on exposure to moisture from the mouth and as such, lip comfort with conventional paper straws are inferior to plastic straws.

3. The internal surface of a conventional paper straw has a high level of cellulose fibre exposure due to the way the straws are manufactured. Each individual fibre provides a nucleation site for carbonated beverages. As such, with carbonated beverages, there is a tendency for the dissolved gas within the beverage to be "released" via the nucleation site resulting in an amount of frothing or fizzing of the beverage. This can result in significant beverage spillage from its container.

4. While there is a trend to move away from plastic straws to more environmentally friendly alternatives such as paper straws, wet strength resin containing papers are only repulpable and recyclable with the incorporation of additional steps, specialist chemicals or particular conditions such as high temperature environments, in order to process and remove the resin adhesives. Such straws are therefore not directly repulpable or recyclable.

5. Conventional compression techniques that are typically used to create the concertina pattern in a plastic straw do not reliably allow paper straws to be bent with bend angles beyond around 60 degrees from the elongate direction or plane of the straw.

Summary

Aspects of the invention are set out in the independent claims and preferred features are set out in the dependent claims.

According to a first aspect there is provided a straw comprising: a first straight portion; a second straight portion; a bendable portion arranged between the first straight portion and the second straight portion and comprising a screw thread configuration, wherein the bendable portion is configured to bend to position the first straight portion at an angle relative to the second straight portion; and a thermoplastic layer arranged between the plurality of layers comprising paper in at least the bendable portion of the straw.

Advantageously, the bendable portion of the straw comprising a screw thread configuration or shape allows for it to be bent at the bendable portion to a desired bend angle without the material of the straw being kinked, torn or damaged in the bending process, including when cooled to an ambient temperature. This provides for larger bend angles of paper straws to be achieved relative to conventional paper straws. Moreover, the paper straws can be readily repulped and recycled, unlike plastic equivalents. Thermoplastic layers arranged between the paper layers of a straw can improve the properties of the paper, such as enhancing the thermoplastic nature of paper such that greater bend angles can be achieved than with paper alone, and also improves the recyclability of paper straws compared to wet strength paper straws. Paper has a natural thermoplastic quality which can be enhanced and utilised by a thermoplastic coating applied to one or more of the paper layers of the straw. The thermoplastic nature of the paper provides for the straw to be bent, when heated, to a desired shape. For example, the straw can be bent from the straight, tubular structure in which it is manufactured.

The bendable portion optionally has a higher density of paper fibres than the first and second straight portions, which may help the material to bend over the curved portion. As described in more detail below, this can be achieved by allowing the end of the straw to be pulled inwards towards the screw thread portion as the screw thread shape is being formed.

In some embodiments, the thermoplastic layer comprises a coating on one of the layers comprising paper, preferably a water resistant barrier coating. Barrier coating the straws compared to using traditional wet strength or waxed papers advantageously improves recyclability. The barrier-coated paper enables the straw to be easily recycled compared to a typical paper straw. In particular, such a straw can be repulped directly without any pre-processing steps or conditions.

Optionally, the thermoplastic layer is arranged between the plurality of layers comprising paper and extends along the whole length of the straw. Whilst the bendable portion of the straw particularly benefits from increased thermoplasticity, for simplicity of manufacturing, the thermoplastic layer may be disposed along the length of the straw. In addition, if the thermoplastic layer comprises a water-resistant barrier coating, this is beneficial along the length of the straw.

The thermoplastic layer may optionally comprise a heat sealable layer that bonds the plurality of layers comprising paper without the use of an additional adhesive. This can simplify both manufacturing and recycling of the straw.

Optionally, the bendable portion may enable the first straight portion to be bent to an angle of 180 degrees relative to the second straight portion. In such an orientation, the open ends of the straw both face the same direction. The first straight portion may be shorter than the second straight portion. This configuration is typical for drinking straws so that, in use, liquid does not flow too readily from the end disposed in the liquid out of the other end. It also allows for the straw to reach into the carton or glass.

The bendable portion of the straw may optionally be positioned along the length of the straw between the first end of the first straight portion and the second end of the second straight portion by a distance of between 20% and 40%, more preferably 30%, of the length of the straw.

Optionally, the straw may further comprise a first paper layer having an inner surface and an outer surface; and a second paper layer having an inner surface and an outer surface, optionally wherein the first paper layer is configured to be bonded to the second paper layer.

In some embodiments, the paper layers can be bonded by a heat sealable coating applied to the inner surface of the first paper layer and/or the inner surface of the second paper layer. As noted above, the heat sealable coating may simply be the thermoplastic layer. The heat sealable coating can be used instead of wet glues, which may improve the manufacturing process by increasing the speed whilst also improving the strength of the resulting straw.

The first and second paper layers can optionally be coated on their respective outer surfaces with a water resistant barrier coating. Barrier coating the straws compared to using traditional wet strength or waxed papers advantageously improves recyclability while maintaining the waterproof or water resistant properties of the straw. The barrier-coated paper enables the straw to be easily recycled compared to a typical paper straw. In particular, such a straw can be repulped directly without any preprocessing steps.

The water resistant barrier coating may be an acrylic based coating, optionally a styrene free coating. In one embodiment, the coating may be ethylene acrylic acid or an ethylene acrylic acid co-polymer. The coating is preferably applied using a water based dispersion coating method.

Alternatively, the coating is a styrene based coating, for example a synthetic rubber such as styrene butadiene rubber or styrene butadiene block co-polymer or other styrene acrylic.

Other suitable barrier coatings include polymer dispersion coatings wherein the polymers that can be used include modified ordinary styrene-butadienes, different acrylates and methacrylates, polyolefins, vinylene acetates, copolymers of these or natural biopolymers.

In an alternative implementation, a natural coating may include engineered or modified starch, vegetable oil or a natural wax.

The above coating materials each have water resistant barrier coating and thermoplastic properties. However, in order to tune the thermoplastic properties of polymer coatings, the molecular length (or molecular weight) of the polymer can be varied to alter the glass transition temperature, Tg, of the coating. Tg defines the temperature at which the polymer transitions from a hard material to a soft, malleable, rubbery material and hence defines the temperature at which the coating functions as a thermoplastic.

The To selected will depend on the intended use of the straw (cold liquid / hot drink use), but preferably lies between about 60 or 70 degC and about 120degC.

Altering To for the coating material also enables the polymer to act more effectively as a heat seal.

The paper used in the straw, coated with the barrier coating, is optionally free of wet strength chemicals and wet strength resins and is therefore non wet strength paper.

Wet strength paper is typically more difficult to recycle than paper coated with a water resistant barrier coating due to the additional chemicals incorporated into the paper to increase its wet strength.

The coating itself is preferably recyclable such that all the elements of the straw that make up the different layers are capable of being easily recycled. In particular, the straw is preferably repulpable directly, without any additional processing steps.

The water resistant barrier coating can be applied to the paper from which the straw will be made via one of: an on machine coater, an off machine coater or a printing machine. Other techniques that can suitably and reliably provide a thin film of coating over the paper may be used.

Optionally, in a particular embodiment, the weight of paper used for each of the first paper layer, the second paper layer and the core is less than 120gsm, preferably 100gsm, further preferably 80gsm. In some embodiments, the weight of paper used for each of the first paper layer, the second paper layer and the core is the same for each layer. However, the weight of paper of each of the layers may also be different.

The finished straw comprises a hollow cylinder and may be formed by the paper layers being spirally wound and then bonded together.

The straw may optionally configured to be sealed in a preferably non-plastic overwrap. This overwrap may be attached to a drinks carton or the like, such that the drink and attached straw can be used together.

According to a first aspect there is provided a method of shaping a straw comprising a plurality of paper based layers, the method comprising: providing a straw having a plurality of layers comprising paper and a thermoplastic layer; heating the straw to a predetermined temperature; retaining at least a portion of the straw on a mandrel; forming a screw thread shape in the portion of the straw around the mandrel to provide a bendable portion in the straw between a first straight portion and a second straight portion.

Advantageously, the straw being manufactured and shaped when heated provides for 113 the natural thermoplastic qualities of paper and the additional thermoplastic properties of the thermoplastic layer to be utilised. Forming a screw thread shape, as opposed to the more conventionally seen concertina/embossed-style shape, beneficially provides greater flexibility for the paper straw to be bent without being damaged. The screw thread shape formed around the mandrel beneficially increases the density of fibres in the bendable area. This helps improve the strength of the paper, which in turn allows for a greater degree of flexibility.

Optionally, the mandrel comprises a screw thread shape. Beneficially this may guide the straw, in particular the bendable portion of the straw into the desired screw thread pattern.

Providing the straw optionally comprises forming the straw from a plurality of layers of a paper-based material in a spiral winding process.

In some embodiments, the screw thread shape is formed along the straw from one end of the bendable portion to the other end of the bendable portion, for example, in one continuous motion. Forming the screw thread portion in this way enables material to be drawn into the screw thread portion of the straw as it is formed, leading to a higher density of material in the screw thread portion. This ensures that there is sufficient material in the bendable portion of the straw to enable the straw to bend without kinking or tearing.

The screw thread shape may optionally be formed by indenting the surface of the straw while rotating the straw. Optionally the straw is cut to a predetermined length.

In some embodiments, the method further comprises pre-treating at least one layer of the straw with a thermoplastic coating. The thermoplastic coating may enhance the thermoplastic characteristics of the paper such that it can be bent with a greater degree of flexibility compared to paper without a thermoplastic coating. Optionally, the method may further comprise curving the straw into a desired configuration while the straw is still heated. This may be aided by the thermoplastic coating. The method may further comprise cooling the straw.

The predetermined temperature may be between 60 degrees and 120 degrees, more preferably around 70 degrees. Increased temperatures may improve the flexibility of the paper, whilst lower temperatures are preferred for safety and to reduce production cost.

Brief Description of the Drawings

Exemplary embodiments are illustrated in the accompanying figures in which: Figures 1 and 2 illustrate an exemplary structural composition of a two layer drinking straw according to one embodiment; Figures 3 and 4 illustrate perspective views of an exemplary straw according to one zo embodiment; Figure 5 illustrates exemplary packaging of an exemplary straw according to one embodiment; Figure 6 is a perspective view of an exemplary straw according to one embodiment; Figure 7 is a schematic illustration of a paper straw according to one embodiment.

Detailed Description

Figure 1 illustrates a first paper layer 10 coated on an outer surface with a coating 20 and on an inner surface with a coating 21. Coating 20 may have water resistant properties, depending on the type of paper used in manufacturing the straw. The coating 20 comprises thermoplastic properties and hence enhances the thermoplastic properties of the paper layer 10. Coating 21 may also be a heat sealable coating as mentioned above. It may also be beneficial for coating 21 to be water resistant. Coating 20 and coating 21 may have the same characteristics and be made from the same materials, or may have different characteristics.

A second paper layer 12 is coated on an outer surface with a coating 22 and coated on an inner surface with a coating 23. Coating 22 may be the same as coating 20 and coating 23 may be the same as coating 21. In preferred embodiments, the coatings are all be the same.

Thermoplastic coatings 21 and 23 can enhance the natural thermoplastic characteristics of paper such that the straw can be bent whilst heated and retain its shape once cooled. The coatings on the inner surfaces of the layers may also be heat sealable such that the layers can be bonded using heat only, without the need to use adhesives such as glues.

Coating of all the surfaces of the paper may not be necessary, and coating a minimum number of surfaces can help reduce the overall cost as well as reduce manufacturing time and complexity. However, the outer surfaces of the straw should have some water resistance. At least one inner surface can be coated with a heat sealable coating that allows the layers to be fixed, in particular adhered, without using wet glues, which may further simplify the manufacturing process and eliminate straw drying times. Paper straws are typically made with two or more layers of paper sheets rolled, or spirally wound, into a tubular structure. Heat sealable coatings may become tacky when heated and allow the winding process to be completed and the layers fixed in place without using wet glues.

Figure 2 illustrates the first paper layer 10 bonded, for example stuck or adhered to, the second paper layer 12 at an interface 25 between the layers.

A water resistant coating being deposited on either side of the paper layers advantageously improves the seal or interface between the paper layers against moisture. In the spiral winding process that binds the paper layers together to form a tube, internal layers can be exposed at sites which are not properly bonded. Moisture can get into the straw via these sites, which can cause the straw to fail. If the coatings 21 and 23 act as a water resistant barrier coating, the sealing between layers can be improved and moisture pervasion can be significantly reduced.

Figure 3 illustrates a paper straw 3 having a first straight portion 30, a bendable portion 34, and a second straight portion 32. The first straight portion 30 has a first open end and is configured to be arranged adjacent the bendable portion 34. The second straight portion 32 is arranged adjacent the other side of the bendable portion 34 and has a second open end. The elongate length of the straw extends from the open end of the first straight portion 30 to the open end of the second straight portion 32, along a straw axis, the bendable portion 34 being disposed between the first straight portion 30 and the second straight portion 32. The portions of the straw are typically made from a tube of spirally wound paper comprising multiple paper layers.

In use, a user may place their lips around the outside of a first end of the first straight portion 30. The second end of the second straight portion 32, in use, can be deposited in liquid. The user can then draw liquid up through the straw towards their mouth.

The bendable portion 34 is configured with a screw thread shape, which is illustrated in an exaggerated example as shown in Figure 3. The screw thread shape may be achieved by having a density of fibres in the bendable portion being high compared to the straight portions.

The desired location of the bend is typically approximately 30% from one end of the straw.

A densifying process can be used to increase the fibre density at a location along the length of the straw when starting from a straw that has uniform fibre density along its length. During the straw manufacturing process, or in a separate process, the paper straw can be prepared and shaped through use of the thermoplastic coating. The coated paper is heated and then subjected to a process by which a screw thread pattern is applied to the straw at the bendable portion. The straw may be placed on and rotated around a mandrel, which may comprise a screw thread pattern, at a predetermined temperature (between 60 degrees and 120 degrees) in order for the screw thread pattern to be set in the straw. As the heated straw is rotated with the mandrel, fibres are pulled into the screw threaded area; increasing the density of fibres in that area.

The process of applying a screw thread pattern can also be implemented, for example, by rotationally indenting the surface of the straw. The straw may be rotated on the mandrel, or the like, whilst an external force is applied to the desired location of the bendable portion.

Bendable paper straws can be manufactured in this manner without the need for wet glues, which beneficially provides for the production of straws to be improved by both simplification and speed; in particular by removing drying time that would be needed for a manufacturing process using wet glue.

Figure 4 illustrates a paper straw 4 having a first straight portion 30, a bendable portion 34, and a second straight portion 32, wherein the first straight portion 30 is bent 180 degrees relative to the second straight portion 32.

Whilst the straw is hot, it can be subjected to a bending force to curve the straw to a desired bend orientation e.g. 180 degrees from straight. Whilst still bent to the desired orientation, the straw can then be subjected to a cooling force, for example high velocity cold air, to reduce the temperature of the straw to ambient.

As a result of returning to ambient, rigidity is regained and the straw retains the desired bend angle at which it was positioned during the heated phase. By virtue of the increased density of material in the bendable portion 34, the bent straw can be straightened (and/or bent at a different angle) as desired by the consumer.

Higher density of fibres in the bendable portion 34 allows the straw to maintain integrity and avoid being ripped or torn when being bent under heated conditions.

Heat sealable barrier coatings can be used in a conventional spiral wound process to bind the layers of the straw, but utilize heat and pressure to bond the surfaces together instead of typical adhesives such as glue. Advantageously, this provides for improved speed of manufacturing. The speed is reduced by simplification of the process and a reduced number of steps involved in bonding the layers to one another, as well as not having to spend time waiting for glues to dry.

A water resistant barrier coating may be applied to outer surfaces and/or inner surfaces of the paper layers. Water resistant barrier coatings applied to paper are beneficial over straws which use compounds to make the paper itself water resistant. Replacing traditional wet strength paper with non wet strength paper coated with water based, water resistant barrier coatings advantageously provides for an improved paper straw that is more resistant to liquid damage, such as becoming soggy or limp, and retains the ability to be conventionally recyclable and repulpable.

Non wet strength papers are of a similar grammage (in gsm) to the existing papers used, and thus look and feel similar to conventional paper straws. The straws pertaining to this application comprise papers which are water resistant by virtue of their barrier coating, and do not employ water resistance by virtue of compounds added to the paper material itself. The water based coating imparts, when dry, a high level of grease and water resistance to the paper surface, giving additional structure and integrity to the paper. The papers used are conventionally repulpable without additional processing steps to first remove any of the coating layers or additives and/or biodegradable for example through composting.

In contrast, wax coated papers are unsuitable for recycling and many existing straws made using wet strength papers require separation and additional processing at recycling plants in order to break down the chemicals and additives used to improve the paper strength and are therefore difficult to recycle in conventional recycling centres.

The coatings used in embodiments of the straw described herein are typically food safe, styrene-free, acrylic based coatings but can include styrene-butadiene (SBRs), styrene acrylics and other lattices known to provide water resistance, or any of the coating materials described above.

The coatings can be applied via: on-machine coaters at the paper machine, off-machine coaters or via printing processes. The printing of the coating may depend on the coating weight or required thickness as well as placement.

Coatings can be dispersed by application to the surface of paper, or other easily pulpable, suitable materials, to form a solid, non-porous film. After the film is dried, it provides a barrier layer against water (and/or water vapour) and other substances such as grease, oil and other gases.

The paper layers of the straw are coated on both sides and the inner coatings provide properties that allow bonding of the paper layers in the straw via heat rather than glue.

In addition, the coating layers are of a thermoplastic nature, which allows softening under heated conditions such that the material can be bent into shape but will regain rigidity once cooled to ambient conditions.

The paper layers can each be made from the same type of paper, although they may comprise different thicknesses or grammages (in gsm) of paper, for example. It will be appreciated that different papers could be used on each of the different paper layers. The outer or second layer, for example, may have a lower gsm to the inner and core paper layers since a finer paper is smooth and therefore tends to have an improved mouth feel. The second paper layer 12 may be decorated, for example, with a different colour or pattern to the other layers so as to be more pleasing or interesting to a consumer.

Moisture resistance is improved compared to a standard straw construction so softening of the straw is delayed significantly compared to other coatings. A straw's useful operational time can be improved from around 30 minutes to a couple of hours or more. Moisture resistance is also beneficial in the manufacturing process, where the machines used to manufacture the materials, and as a result the materials themselves, are subjected to cooling fluids.

A food safe, smooth, barrier coating applied to the outer layer of the straw provides a user with a comfortable surface on which to place the lips, which can be achieved without the need for expensive, extra smooth papers, as is commonly done. The comfortable quality of the outer surface is maintained longer than a conventional paper straw, and shows similar performance of comfort level to a plastic straw.

The inner surface of the paper straw being coated with a food safe barrier coating provides for the cellulose fibres, which are normally exposed, to be covered. As such, a barrier coated paper straw construction eliminates the frothing or fizzing problem seen with conventional paper straws when used with carbonated beverages, which may occur at nucleation sites that appear due to poor sealant of the paper layers.

Without wet strength resin, the barrier coated paper straw construction is conventionally recyclable and repulpable which provides environmental benefits over wet strength paper straws.

Paper straws made in the above manner may advantageously be made in a number of sizes, and configurations and maintain the integral strength to withstand being bent to 180 degrees.

Figure 5 illustrates an exemplary way of packaging a paper straw 4 with a 180 degree bend, which provides for a straw to be individually packed in its own sealed pouch 50.

Typically, small bendy straws, such as those appended to a drinking carton or the like, come with an additional overwrap suitable for automated filling, which is also usually made of plastic. Packing lines also traditionally use plastics.

The packaging, for example an overwrap, may comprise biodegradable and repulpable materials, such as paper materials or cellophane (for example cellulose cellophane) or a combination of materials. The straws are individually sealed to provide protection against moisture and contaminants and are designed such that they can be easily attached to a drinking carton and used "on-the-go".

Preferably, the materials of the overwrap are coated in a heat-sealable coating to enable the straws to be sealed between layers of the overwrap in individual cells or packets using a heat-sealing technique. The heat sealable coating may be the same composition as the thermoplastic or barrier or heat sealable coatings described above.

In a particular embodiment, the overwrap comprises one layer of a paper-based material, which would be opaque, and a second layer of a cellulose-based material such as cellophane, which is transparent or at least translucent. This enables the user to see the straw before the overwrap is opened while reducing the costs that would be associated with an all-cellulose-based material.

Figure 6 illustrates a perspective view of an exemplary straw according to one embodiment. The layers of the straw have been spirally bound, such that the outer surface of the straw is the second paper layer 12. The spiral winding process leaves weak points 50 on both surfaces of the straw that can be susceptible to liquid penetration. The straw comprises a hollow cylinder. In use one end of the straw is placed in a liquid whilst the other end is placed in a user's mouth.

Figure 7 is a schematic illustration of a paper straw according to one embodiment. The straw comprises an inner surface 10, a core 14, and an outer surface 12. The layers are spirally wound to create the hollow tubular structure as illustrated.

It will be appreciated from the above description that many features of the different examples are interchangeable and combinable. The disclosure extends to further examples comprising features from different examples combined together in ways not specifically mentioned. Indeed, there are many features presented in the above examples and it will be apparent to the skilled person that these may be advantageously combined with one another.

Claims

Claims 1. A straw comprising a plurality of layers comprising paper, the straw comprising: a first straight portion; a second straight portion; a bendable portion arranged between the first straight portion and the second straight portion and comprising a screw thread configuration, wherein the bendable portion is configured to bend to position the first straight portion at an angle relative to the second straight portion; and so a thermoplastic layer arranged between the plurality of layers comprising paper in at least the bendable portion of the straw.
2. The straw of claim 1 wherein the bendable portion has a higher density of paper fibres than the first and second straight portions.
3. The straw of claim 1 or 2 wherein the thermoplastic layer comprises a coating on at least one of the layers comprising paper.
4. The straw of any preceding claim wherein the thermoplastic layer comprises a water-resistant barrier coating.
5. The straw of any preceding claim wherein the thermoplastic layer is arranged between the plurality of layers comprising paper and extends along the whole length of the straw.
6. The straw of any preceding claim wherein the thermoplastic layer comprises a heat sealable layer that bonds the plurality of layers comprising paper without the use of an additional adhesive.
7. The straw of any preceding claim wherein the bendable portion enables the first straight portion to be bent 180 degrees relative to the second straight portion.
8. The straw of any preceding claim wherein the first straight portion is shorter than the second straight portion.
9. The straw of any preceding claim wherein the bendable portion is positioned along the length of the straw between the first straight portion and the second straight portion by a distance of between 20% and 40%, more preferably 30%, of the length of the straw.
10. The straw of any preceding claim wherein the plurality of layers comprises: a first paper layer having an inner surface and an outer surface; and a second paper layer having an inner surface and an outer surface.
11. The straw of claim 10 wherein the inner surface of the first paper layer is configured to be bonded to the inner surface of the second paper layer.
12. The straw of claim 10 or claim 11 wherein the first and second paper layers are coated on their respective outer surfaces with a water resistant barrier coating, optionally comprising the same composition as the thermoplastic layer.
13. The straw of any preceding claim wherein the thermoplastic layer comprises an acrylic based coating.
14. The straw of claim 13 wherein the acrylic based coating is styrene free.
15. The straw of any of claims 1 to 13 wherein the thermoplastic layer comprises a styrene based coating.
16. The straw of any preceding claim wherein the paper layers are free of wet strength chemicals and wet strength resins.
17. The straw of any preceding claim wherein the straw is repulpable.
18. The straw of any preceding claim wherein the straw is biodegradable and/or recyclable.
19. The straw of any of claims 12 to 18 wherein the barrier coating is applied via one of: an on-machine coater; an off-machine coater; and/or a printing process.
20. The straw of any preceding claim where the weight of paper used for each of the first paper layer and the second paper layer is less than 120gsm, preferably 100gsm, further preferably 80gsm.
21. The straw of claim 20 wherein the weight of paper used for each of the first paper layer and the second paper layer is the same for each layer.
22. The straw of any preceding claim wherein the straw is configured to be spirally wound.
23. The straw of any preceding claim configured to be sealed in a non-plastic overwrap.
24. A method of shaping a straw comprising a plurality of paper based layers, the method comprising: providing a straw having a plurality of layers comprising paper and a thermoplastic layer; heating the straw to a predetermined temperature; retaining at least a portion of the straw on a mandrel; forming a screw thread shape in the portion of the straw around the mandrel to provide a bendable portion in the straw between a first straight portion and a second straight portion.
25. The method of claim 24 wherein the mandrel comprises a screw thread shape.
26. The method of claim 24 or 25 wherein providing the straw comprises forming the straw from a plurality of layers of a paper-based material in a spiral winding process.
27. The method of any of claims 24 to 26 wherein the screw thread shape is formed along the straw from one end of the bendable portion to the other end of the bendable portion.
28. The method of any of claims 24 to 27 wherein forming the screw thread shape comprises indenting the surface of the straw while rotating the straw.
29. The method of any of claims 24 to 28 further comprising cutting the straw to a predetermined length.
30. The method of any of claims 24 to 29 further comprising pre-treating at least one layer of the straw with a thermoplastic coating to form the thermoplastic layer.
31. The method of any of claims 24 to 30 further comprising curving the straw into a bent configuration while the straw is still heated.
32. The method of any of claims 24 to 31 further comprising cooling the straw.
33. The method of any of claims 24 to 32 wherein the predetermined temperature is between 60 degrees and 120 degrees, more preferably around 70 degrees.