SCREW THREADS

Description

BACKGROUND

Containers are often provided with a closure, such as a cap or lid. Such closures may be single use, for example a film may be fixed across an opening of a container using an adhesive. In other examples closures may be reusable, such that the container may be openable by removing the closure and it may be closed again by replacing the closure. For example a lid or cap may be fitted to an opening of a container using push fit, a screw thread or other reusable closure method. An opening of a container may be provided with a screw thread to engage a lid or a cap with a corresponding screw thread to close the container.

BRIEF DESCRIPTION OF DRAWINGS

Non-limiting examples will now be described with reference to the accompanying drawings, in which:

FIGS. 1A and 1B are simplified schematics of an example of a closure engaging part;

FIG. 2 is a simplified schematic of an example container;

FIG. 3 is a simplified schematic of an example container;

FIG. 4 is a flowchart of an example of a method of forming a molded fiber object;

and

FIG. 5 is a flowchart of an example of a method of providing a container with a screw thread.

DETAILED DESCRIPTION

A molded fiber object may be an object formed using a fiber molding process, such as a wet pulp molding process or a dry fiber molding process.

In a wet pulp molding process, the object may be formed on a pulp molding die comprising a screen, and a form which supports the screen. The screen may comprise a plurality of small openings, or pores, which allow liquid to flow through. The screen may be separable from the form. The form may comprise any element which provides structural support for the screen which helps it to maintain its shape while forming an object. The form may also comprise holes or channels through which fluids may flow to and from the screen. In some examples the pulp molding die may be formed from a metallic material or from a plastic material. In some examples they may be manufactured using machining techniques, such as CNC (Computer Numerical Control) milling or additive manufacturing. The screen may be a woven mesh formed from a plurality of fine metal wires.

Wet pulp molding processes may comprise covering the screen of a pulp molding die with a slurry, or pulp, comprising a liquid component, such as water, and a solid, fibrous material. The screen of the pulp molding die may comprise a surface having a shape which corresponds to the shape of a surface of an object to be formed using the die. The die may be submersed in a bath of the slurry to cover the screen of the die. The screen of the pulp molding die may comprise pores (i.e. small holes, or porous zones) in the surface which allow the liquid component of the slurry to pass through, but are sufficiently small that the solid, fibrous material accumulates on the surface of the screen to form the object. The formed object may then be dried, for example by heating in an oven or between dies (e.g. metal dies), to form the finished molded fiber object.

In some examples heating between dies may be referred to as hot pressing the object. Hot pressing may provide a higher surface quality and/or more precise dimensions than forming an object without hot pressing.

In other examples a dry molded fiber process may be used to form a molded fiber object. In a dry molding process, loose, dry fibers may be provided between sheets of a tissue material and the object may be formed by applying heat and/or pressure to the sheets of tissue material while the sheets of tissue material and fibers is on a mold.

In order to reduce the amount of plastics used in packaging and to increase the ease of recycling packaging, molded fiber has been used as packaging for a wide variety of products. However, molded fiber objects are often formed from materials, such as recycled paper or cardboard, which are susceptible to damage when exposed to moisture. Furthermore providing a closure which is suitable for containing liquids may be challenging. To provide molded fiber packaging for wet products, a waterproof layer may be added to an interior surface of the packaging, for example a coating or a film, or in other examples a waterproof container, such as a plastic container may be provided within the molded fiber packaging.

As used herein, a closure is an item which may be used to close, or seal, a container. For example a closure may be a lid, cap or sealing film. Closures have been provided for molded fiber containers, for example by sealing a film to an opening of the container using an adhesive or by providing an insert, made from a material such as plastic or metal, which is secured around the opening of the container. Such inserts may have a screw thread to allow a lid or cap to be screwed on to the container, however, they can add substantial cost and complexity to manufacture of the container. Furthermore, they significantly increase the complexity of recycling the container because the different types of material may be to be separated into different recycling streams.

Inserts have been used to provide a thread for attaching a closure to molded fiber containers because it is challenging to form a thread directly in the container. Generally, forming small features with precise dimensions using molded fiber materials is more difficult compared with other manufacturing techniques (e.g. injection molding or blow molding which may be used to form plastic bottles with screw threads). It may be particularly challenging to form the screw thread around a circular opening of a container. Furthermore, molded fiber containers may be formed from multiple parts which are subsequently assembled. In such examples if the screw thread was formed with the body of the container, it may extend over multiple parts of the container resulting a need to accurately align the multiple parts of the container resulting in further manufacturing challenges.

FIGS. 1A and 1B show a closure engaging part 100. FIG. 1A shows an outer surface of the closure engaging part 100 i.e. the surface which faces away from a container the closure engaging part 100 is affixed to when in use. FIG. 1B shows an inner surface of the closure engaging part 100 i.e. the surface which faces towards a container when the closure engaging part 100 is affixed to when in use.

In some examples the closure engaging part 100 is formed from a compostable material. In some examples the closure engaging part 100 is a molded fiber part i.e. a closure engaging molded fiber part 100. Such a closure engaging molded fiber part 100 may be formed using a pulp molding process, for example from a material such as recycled paper or cardboard.

The closure engaging part 100 may be intended to be used to reversibly attach a closure, such as a lid with a screw thread, to a container to seal the container. The closure engaging part 100 may be attached to a container such that when a lid is arranged on the closure engaging part 100, the closure engaging part 100 engages the lid to hold it in a position that closes the container. For example a closure may be rotated about an axis and a screw thread of the lid may engage a screw thread of the closure engaging part 100 to secure the closure in position at an opening of the container.

The closure engaging part 100 comprises a plurality of threaded portions 102a-c. A portion of a screw thread is provided on each threaded portion 102a-c. As used herein a screw thread is a helical structure which provides linear movement or force when an object, such as a lid, with a corresponding screw thread is rotated about the screw thread. When the closure engaging part 100 is wrapped around an opening of a container, the portions of screw thread on adjacent threaded portions may align such that they collectively form a screw thread around the opening i.e. the portions of screw thread may be colinear with portions of screw thread on an adjacent threaded portion(s). In some examples, the portions of screw thread are raised portions of material, such as molded fiber material. For example, the screw thread may comprise oblique raised linear features, or ‘ridges’, which when wrapped around an opening of a container align to provide a (partial) screw thread for the container. In some examples, at least one or each threaded portions 102a-c may comprise a plurality of substantially parallel ridges, each ridge forming part of the screw thread. The ridges on a threaded portion 102a-c may be substantially straight, or may have a curved or arc-like form. When the closure engaging part is in use, the raised portions of material may align to form a screw thread which may extend around a substantial part of an opening of a container to which the closure engaging part 100 is affixed.

In examples wherein the closure engaging part 100 is a closure engaging molded fiber part, the portions of screw thread may be defined in a pulp molding screen which is used to form the closure engaging molded fiber part 100. For example the screen may comprise raised portions which cause the closure engaging molded fiber part 100 to have corresponding raised portions when it is formed on the screen. In some examples the closure engaging molded fiber part 100 may undergo further processing after being formed in the fiber molding process to define the screw threads, for example as described in relation to FIG. 5.

The closure engaging part 100 comprises a flexible portion 104a-b between and connecting pairs (e.g. adjacent pairs) of threaded portions. As shown in the FIGS. 1A and 1B the flexible portions 104a-b may not comprise a screw thread. In some examples the flexible portions 104a-b may be free of any raised topography, for example be substantially planar. The flexible portions 104a-b are more flexible than the threaded portions 102a-c. The absence of any raised topography on the flexible portions 104a-b may allow them to be more flexible than the threaded portions 102a-c. In some examples the flexible portions may comprise some topography, for example debossed, engraved or raised features, but it may be such that it allows the flexible portions 104a-b to remain more flexible than the threaded portions 102a-c. For example the topography of the flexible portions 104a-b may be smaller than the topography of the threaded portions 102a-c i.e. the topography may be of a smaller height and/or cover a smaller proportion of the surface area of the flexible portions 10a-b relative to the threaded portions 102a-c. In some examples the flexible portions 104a-b may comprise debossed, engraved or raised topography that extends substantially parallel to the axis of the screw thread (i.e. a central axis of the screw thread when the closure engaging part 100 is arranged around a container opening and about which a closure may be rotated to cause a screw thread of the closure to engage with the axis) and therefore allows the flexible portions 104a-b to bend or curve along this axis. In examples wherein the flexible portions comprise some topography the height of the topography may be sufficiently small that it does not interfere with operation of the screw thread i.e. it does not obstruct a threaded cap from engaging with the screw thread.

In some examples the flexible portions 104a-b may be thinner than the threaded portions 102a-c to allow then to have greater flexibility. In other words, the thickness of the 30 material forming the threaded portions 102a-c may be greater than the thickness of the material forming the flexible portions 104a-b. For example the material forming the flexible portions 104a-b may have a thickness of 0.6 mm and the material forming the threaded portions 102a-c may have a thickness in the range of 0.6 mm to 1.8 mm. For example the thickest parts of the threaded portions 102a-c (e.g. the raised threads) may have a thickness of 1.8 mm and other parts of the threaded portions 102a-c (e.g. between the threads) may have a thickness of 0.6 mm. Therefore in some examples only parts of the threaded portions 102a-c may be thicker than the flexible portions 104a-c. In some examples most, or all, of the threaded portions 102a-c may be thicker than the flexible portions 104a-b.

In some examples, for example as shown in FIG. 1B, rather than varying the thickness of the threaded portions 102a-c to provide the screw thread, the threaded portions 102a-c may have a substantially constant thickness but have an undulating or ‘wavy’ profile to provide the screw thread.

In some examples, the increased flexibility of the flexible portions 104a-b may be provided by removing material from these sections. For example an opening or openings (e.g. holes) may be provided in the flexible portions. In some examples these openings may be formed as part of a fiber molding process. In some examples these openings may be cut out of the flexible portions 104a-b after the closure engaging part 100 is formed. In some examples the openings may be notches extending from a top and/or bottom edge of the flexible portions 104a-b. In other words a notch may be a hole which is not entirely surrounded by material.

In some examples the closure engaging part 100 comprises at least three threaded portions 102a-c and two flexible portions 104a-b. The closure engaging part 100 shown in FIGS. 1A and 1B comprises three threaded portions 102a-c and two flexible portions 104a-b. However, in other examples there may be more or fewer threaded portions and/or flexible portions. For example a closure engaging part may comprise two threaded portions with one flexible portion between the threaded portions, or a closure engaging part may comprise four threaded portions with three flexible portions between the threaded portions. In some examples the closure engaging part may comprise a further flexible portion (or portions) at one end (or both ends) of the closure engaging part attached to a single threaded portion. Therefore, for a closure engaging part with N threaded portions, the number of flexible portions may be N−1 if there are no end flexible portions, N if there is one end flexible portion, or N+1 if there are flexible portions at both ends.

When there are fewer threaded portions 104a-b, the curvature of the threaded portions is larger and therefore manufacture may be more challenging. However, reducing the curvature of the threaded portions by increasing the number of threaded portions results in reduced total threaded area on the closure engaging part 100 due to the increased number of flexible portions. As shown in FIGS. 1A and 1B, the closure engaging part may comprise three threaded portions 102a-c and two flexible portions 104a-b. This may provide a balance between a closure engaging part 100 which has sufficient ease of manufacturing and flexibility to be easily wrapped around an opening of a container (i.e. by providing a larger area of flexible portions) and a closure engaging part 100 which has a substantial threaded area (i.e. by providing a larger area of threaded portions).

In some examples, for example as shown in FIGS. 1A and 1B, the threaded portions 102a-c may be larger than the flexible portions 104a-b. This may provide a relatively large threaded area on the closure engaging part 100, thereby providing better engagement with a closure. In some examples the threaded portions 102a-c may form at least 60%, 70%, 80% or 90% of the area of the closure engaging part 100.

As shown in FIGS. 1A and 1B the screw thread of the threaded portions 102a-c may be formed by substantially linear raised portions of material extending along the threaded portions of the closure engaging part 100 in a substantially helical pattern. The dimensions of the screw thread may be defined according to a standard, for example as defined by the Glass Packaging Institute (GPI), the Society of Plastics Industry (SPI) or International Society of Beverage Technologists (ISBT) Threadspecs.

In some examples each threaded portion 102a-c has a circular arc shaped cross section. For example when the closure engaging part 100 is viewed in a direction parallel to the axis of the screw thread (wherein the axis is the axis about which a closure may be rotated to engage with the screw thread) the cross sectional shape of the threaded portions may be of an arc of a circle so that when the closure engaging part 100 is affixed to a container with a circular opening, the relatively rigid threaded portions conform to the shape of the opening. Therefore the internal radius of curvature of the threaded portions 102a-c may be equal to the exterior radius of the opening of the container. For example a container may have an opening with an exterior radius of 1.5 cm. The threaded portions 102a-c of a corresponding closure engaging part 100 may have an internal radius of curvature of 1.5 cm.

The closure engaging part 100 may have a generally rectangular shape. For example when in a plan view, prior to wrapping the closure engaging part 100 around a container, the closure engaging part 100 may have a rectangular shape. Furthermore each of the threaded portions 102a-c and each of the flexible portions may also have a generally rectangular shape from this view.

The total length of closure engaging part 100 in a direction perpendicular to the axis of the screw thread may be equal to or less than an outer circumference of an opening of a container the closure engaging part 100 is to be affixed to, so that when the closure engaging part 100 is affixed to the container, a screw thread is provided around a substantial portion of the opening of the container. In the example above, for a container with an opening with an outer radius of 1.5 cm, the length of the closure engaging part 100 may be 9.4 cm (i.e. almost as long as the outer circumference of the opening of the container).

The length of each threaded portion 102a-c in the direction perpendicular to the axis of the screw thread may be greater than the length of each flexible portion 104a-b in this direction to provide a relatively large area of screw thread. In the example described above, for a container with an opening with an outer radius of 1.5 cm, and a closure engaging part 100 comprising three threaded portions 102a-c separated by two flexible portions 104a-b, the length of the threaded portions may be 2.4 cm and the length of the flexible portions may be 1.1 cm to provide the total length of 9.4 cm

In some examples the screw thread of the closure engaging part 100 is at least partially formed using a hot pressing process. Hot pressing the closure engaging part 100 may comprise placing the closure engaging part 100 between heated dies (e.g. metal dies), wherein the shape of the surfaces of the dies corresponds to the intended shape of the finished closure engaging part 100. The dies may define the shape of the screw thread i.e. at least one die may comprise surface topography that corresponds to the intended shape of the screw thread. When the closure engaging part 100 is placed between the dies, heat and/or pressure may be applied so that the closure engaging part 100 conforms to the shape of the dies. When the closure engaging part is a molded fiber object, hot pressing may allow more accurate shapes to be formed compared with molded fiber objects which do not undergo a hot pressing process. In particular hot pressing may allow more accurate and finely detailed shapes to be formed in the object. Therefore hot pressing may allow better definition of the screw thread. The hot pressing process may also partially or wholly dry the closure engaging molded fiber part 100, such that it may be formed with or without a further drying process (e.g. in an oven).

Hot pressing may also be referred to as fiber thermoforming. Molded fiber objects which are formed using a hot pressing process may be referred to as Type-3 Molded Fiber Products, Thermoformed products or thin wall products. Such molded fiber objects may have a wall thickness of less than 4 mm. For example the flexible portions 104a-b of the closure engaging molded fiber part 100 may have a thickness of 0.6 mm and the threaded portions of the closure engaging molded fiber part 100 may have a thickness in the range of 0.6 mm to 1.8 mm. For example the total thickness at the locations of the raised threads may be 1.8 mm and the thickness of the threaded portions 102a-c may be 0.6 mm between the threads.

In some examples cold pressing may be performed instead of hot pressing to form the portions of screw thread. Cold pressing may comprise applying pressure to an object being formed between dies without heating.

By providing the screw thread on a closure engaging molded fiber part 100 rather than directly on a molded fiber container body, hot pressing may be performed on the relatively small closure engaging molded fiber part 100 rather than on the relatively large container body. In some examples, this may avoid subjecting the container body to hot pressing in order to accurately define a screw thread. Hot pressing is an additional process and therefore adds additional cost and time to manufacture. Furthermore, by providing the screw thread on a closure engaging molded fiber part 100 rather than directly on the container body, a single design of container body may be used for threaded and non-threaded containers. This provides manufacturing flexibility because the decision to add the closure engaging molded fiber part to a container may be made after the parts are manufactured. Furthermore, costs are reduced because the same fiber molding toolsets can be used for both threaded and non-threaded containers.

In some examples the flexible portions 104a-b and threaded portions 104a-c are integrally formed in a fiber molding process, for example they may be formed in a single fiber molding process. This fiber molding process may define the screw thread, however, in some examples the threaded portions 104a-c may be formed with a roughly defined screw thread or with no screw thread in the fiber molding process and definition of the screw thread may be provided by an additional hot pressing process.

In some examples the closure engaging part 100 further comprises a securing means. For example the securing means may comprise an adhesive or mechanical fixing. The securing means may be provided to allow the closure engaging part 100 to be affixed to a container, in particular to allow it to be affixed around an opening of a container to provide a screw thread for attaching a closure to the container. The closure engaging part 100 may be glued (for example, permanently, or substantially permanently) to the container using an adhesive. For example an industrial labelling process may be used to apply a coating of adhesive to the closure engaging part 100, to the container or both and then the closure engaging part 100 may be wrapped around the opening of the container to affix the closure engaging part to the container.

In some examples a mechanical fixing may be used to attach the closure engaging part 100 to the container, either alone or in combination with an adhesive. The mechanical fixing may comprise an additional component such as a ring, which may be formed from plastic or metal, which is inserted over the opening of the container after the closure engaging part 100 is wrapped around the opening to hold the closure engaging part 100 in position. In other examples the mechanical fixing may comprise spikes, clips or other means to hold the closure engaging part 100 in position. In other examples the mechanical fixing may comprise a ratcheting means which secures the closure engaging part 100 in position, for example a cable tie or similar device may be secured around the closure engaging part 100 when it is wrapped around the opening of the container. In other examples the mechanical fixing device may have elastic properties, for example it may be an elastic band or O-ring type rubber ring which is placed around the closure engaging part 100 when it is wrapped around the opening.

In some examples the closure engaging part 100 may be formed with a groove and/or protrusion to align such a mechanical fixing device.

FIG. 2 shows an example of a container 200. The container 200 may comprise a molded fiber body 202. In this example the body 202 is a bottle however, in other examples the body 202 may be a jar or any other container with a circular opening.

The container 200 comprises a closure engaging part 204 secured around the opening of the body 202, in this example around the neck of the bottle. The closure engaging part 204 may be a closure engaging part 100 as described in relation to FIGS. 1A and 1B. In some examples the closure engaging part 204 is a closure engaging molded fiber part. In some examples at least one of the closure engaging part 204 and the container 200 are formed from molded fibers. In some examples both the closure engaging part 204 and the container 200 are formed from molded fibers.

The closure engaging part 204 comprises a first threaded portion 206a comprising a first portion of a screw thread and a second threaded portion 206b comprising a second portion of a screw thread. In other examples the closure engaging part 204 may comprise more than two threaded portions 206a-b, for example it may comprise three threaded portions.

The closure engaging part 204 also comprises a flexible portion 208 without a screw thread connecting the first and second threaded portions 206a-b. In other examples, in particular although not exclusively, when there are more than two threaded portions, the closure engaging part 204 may comprise more than one flexible portion 208. When the closure engaging part 204 is initially formed, the flexible portion may be substantially flat, but when assembled by wrapping the closure engaging part 204 around the opening of the body 202 of the container 200 the flexible portion 208 may bend to conform to the shape of the opening. The closure engaging part 204 may therefore encircle the opening. The closure engaging part 204 may therefore provide a screw thread around a substantial portion of the opening such that a lid with a corresponding screw may be fitted to the opening to seal the opening.

The closure engaging part 204 may be secured around the opening of the body 202. The closure engaging part 204 may be secured using at least one of an adhesive, a tape or a mechanical fixing. An adhesive or a tape (e.g. double sided tape) may be applied to the closure engaging part 204 or to the body 202 then the closure engaging part 204 may subsequently be relatively wrapped around the body 202. Pressure may be applied to the closure engaging part to ensure the closure engaging part 204 adheres to the body 202. For example a die or dies may surround the body 202 (and in some examples may fit inside the opening of the body) to exert a force on the closure engaging part 204 towards a central axis of the body 202. In some examples an industrial labelling process may be used to apply the adhesive or tape, or to wrap the closure engaging part 204 around the body 202. For example a labelling machine may be modified to handle the closure engaging part 204, the adaptions to the labelling machine being to allow it to handle the closure engaging part 204 which is relatively thick compared with other labels.

In an example, the internal radius of curvature of the threaded portions 206a-b is 11.9 mm and the exterior radius is 12.5 mm. The thickness of the flexible portions may be 0.6 mm and the thickness of the threaded portions may be 0.6 mm to 1.8 mm. The height of the closure engaging part 204 in a direction parallel to the axis of the screw thread may be 17.97 mm (for both the threaded portions 206a-b and flexible portion 208). The length of the flexible portion 208 in a direction perpendicular to its height may be 5.45 mm and the length of the threaded portions 206a-b in a direction perpendicular to their height may be 18.39 mm.

FIG. 3 shows another example of a container 300. The container 300 may comprise the features described in relation to the container 200 of FIG. 2.

In this example the container 300 further comprises a sealing member 302 arranged around the opening of the body 202. In this example the sealing member 302 is a ring-like structure which is positioned on top of the closure engaging part 204. The sealing member 302 may be formed of a material such as plastic, rubber or metal. For example the sealing member 302 may comprise Polyethylene terephthalate (PET), Polypropylene (PP) or Polyethylene (PE). In other examples a sealing member may be provided on or by the closure.

In some examples container 300 may comprise a lining material, in particular when the container 300 is a molded fiber container. The liner may be a water resistant or waterproof material and may allow the container to carry wet products, such as liquids or food without damaging the molded fiber material. The liner may be a coating applied to the interior of the container body 202, a film laminated to the interior of the container body 202 or may be a separate bag-like body which is inserted into the container 300. The sealing member 302 may be bonded to the liner to provide a liquid proof seal between the liner and the sealing member 302. The sealing member 302 may be bonded to the liner using an adhesive or by welding the materials (i.e. melting at least one of the liner or sealing member 302 to cause them to fuse together).

A closure 304 may be screwed onto the screw thread. In this example the closure is a lid comprising an internal screw thread. However, in other examples other configurations may be possible e.g. the closure engaging part 204 may be arranged around the inside of the opening and the closure 304 may have an external screw thread. The closure 304 may be rotated relative to the container 300 so that a screw thread of the closure engages with the screw thread of the closure engaging part 204. When the closure 304 is screwed onto the screw thread, the sealing member 302 provides a seal between the container 300 and the closure 304. In this example sealing is achieved when the sealing member 302 abuts an internal surface of the closure 304. The screw thread allows a force to be exerted between the sealing member 302 and the inside of the closure 304 to provide a liquid proof seal. The sealing member 302 may also protect the opening of the container 200 and the edge of the closure engaging part 204 from being damaged by this force, in particular when the closure engaging part 204 is formed from materials such as molded fibers. Sealing may also be achieved without the presence of the sealing member 302, however, the sealing member may provide a more reliable and durable means for sealing the container 300.

FIG. 4 is an example of a method 400, which may comprise a method for forming a closure engaging object, such as a closure engaging molded fiber object. The closure engaging object may be a closure engaging part as described in relation to FIGS. 1A and 1B or may be a part of the container described in FIG. 2 or 3.

The method 400 comprises, in block 402, forming a plurality of threaded portions of a closure engaging object, each comprising a portion of a screw thread. The plurality of threaded portions may be formed in a fiber molding operation. For example a fiber molding screen may be arranged on a fiber molding form and submersed in a slurry comprising a mixture of fibrous material and liquid. The shape of the screen may correspond to the intended shape of the threaded portions to be formed on the screen. When submersed in the slurry, the liquid may be drawn through the screen causing fibrous material to accumulate on the screen to form the threaded portions. When the threaded portions are formed, the screen may then be removed from the slurry.

The threaded portions may be the threaded portions described in relation to FIG. 1A, FIG. 1B and/or FIG. 2.

The method 400 comprises, in block 404, forming a flexible portion, wherein the flexible portion provides a flexible connection between two of the threaded portions. Forming the plurality of threaded portions and forming the flexible portion may comprise performing a fiber molding operation and the flexible and threaded portions may be formed on a fiber molding screen. The flexible portion may be formed in the same fiber molding operation as the threaded portions. For example a portion of the screen may define the intended topography of the flexible portion and when the screen is submersed in the slurry fibrous material may also accumulate on the screen to form the flexible portion such that the flexible portion connects with, and is formed integrally with, the threaded portions.

In other examples the flexible portion may be formed separately from the threaded portions and subsequently attached to the threaded portions. For example the flexible portion may be formed from a different or the same material as the threaded portions. For example the flexible portions may comprise a paper material and the threaded portions may comprise molded fiber material. The flexible portion may be an adhesive tape, such as a paper tape, and the closure engaging part may be formed by adhering the threaded portions to the tape such that the threaded portions are spaced apart on the tape and the portion of tape between the threaded portions forms the flexible portion.

The flexible portion may be more flexible than the threaded portions, for example (and as discussed in greater detail in relation to FIGS. 1A and 1B) due to an absence of topography, or lower amount of topography on the flexible portion. In some examples (and again as discussed in greater detail in relation to FIGS. 1A and 1B) forming the flexible portion may comprise forming holes or notches in the flexible portion to reduce the amount of material in the flexible portion, thereby increasing the flexibility of the flexible portion.

FIG. 5 shows an example of a method 500, which may comprise a method for providing a container with a screw thread. FIG. 5 provides an example of the method 400 of FIG. 4.

The method 500 comprises, in block 502, forming the plurality of threaded portions and forming the flexible portion in a fiber molding operation, wherein the threaded portions and forming the flexible portion are formed on a fiber molding screen. In some examples the plurality of threaded portions and the flexible portion may be formed in the same fiber molding operation. The plurality of threaded portions may be formed as described in block 402 of FIG. 4 and the flexible portion may be formed as described in block 404 of FIG. 4. In this example both the threaded portions and the flexible portion are formed in a single pulp molding operation.

After the threaded portions and the flexible portions of the closure engaging molded fiber object are formed on the screen they may be removed from the screen, for example by a transfer member. The transfer member may have a shape corresponding to the shape of a surface of the closure engaging molded fiber object. Fluid (e.g. air) may be supplied through openings in the screen to push the closure engaging molded fiber object towards the transfer member and/or a vacuum may be applied to the transfer member to draw fluid (e.g. air) through openings in the transfer member causing the closure engaging molded fiber object to be sucked towards the transfer member.

The transfer member may transfer the closure engaging molded fiber object to heated dies, where in block 504, portions of screw thread on the plurality of threaded portions are formed by hot pressing the plurality of threaded portions. The heated dies may apply heat and/or pressure to the closure engaging molded fiber object. During hot pressing the molded fiber object may be wet from the earlier processes and hot pressing may at least partially dry the closure engaging molded fiber object. In some examples the hot pressing process may completely dry the closure engaging molded fiber object.

One heated die may have a surface with a shape corresponding to the shape of the outer surface of the closure engaging molded fiber object and another heated die may have a shape corresponding to the shape of the inner surface of the closure engaging molded fiber object. The heated dies may define smaller details with higher accuracy than the fiber molding screen. Therefore hot pressing the closure engaging molded fiber object may allow smaller details to be formed more accurately than fiber molding alone. For example the heated dies may define the screw thread more accurately than the fiber molding screen. In some examples the fiber molding screen may not define the screw thread and the screw thread may be entirely defined in the hot pressing process. Hot pressing the closure engaging molded fiber object may also contribute to drying of the closure engaging molded fiber object.

In other examples a cold pressing process may be performed instead of the hot pressing process to form the screw thread portions. In a cold pressing process, the closure engaging molded fiber object may be placed between dies, which are pressed together using a high force to provide a large pressure which is sufficient to define features of the molded fiber object, such as the screw thread portions.

In some examples, the closure engaging molded fiber object may be trimmed after it is formed, either before or after hot pressing. As used herein, trimming refers to cutting excess material from edges of closure engaging molded fiber objects. For example the closure engaging molded fiber object may have rough edges or may have excess material. Trimming the object may provide smooth edges and increased dimensional accuracy. In some examples trimming may comprise removing material from the flexible portion(s) to increase their flexibility. For example holes may be punched through the flexible portion(s) or notches cut from the edges of the flexible portion(s).

The closure engaging molded fiber object may be attached around an opening of a container, for example as described in blocks 506 and 508.

The method 500 comprises, in block 506, providing an adhesive on the container or on the closure engaging molded fiber object. The adhesive may be deposited, spread, painted or otherwise applied to the container or the closure engaging molded fiber object. For example an industrial labelling process may be used to apply the adhesive. The adhesive may be applied to either or both of the container or the closure engaging molded fiber object. For example if the adhesive is a contact adhesive it may be applied to both the container and the closure engaging molded fiber object. In some examples a starch based adhesive may be used.

The method 500 comprises, in block 508, wrapping the closure engaging molded fiber object around the opening of the container to adhere the closure engaging molded fiber object to the container. The flexible portion(s) may bend to conform to the shape of the opening as the closure engaging molded fiber object is wrapped around the opening. The threaded portions may be formed with a shape corresponding to the shape of the opening and therefore may already have an appropriate shape without bending. For example the opening may be circular, and the threaded portions may have a circular arc shape cross-section with an inner radius of curvature equal to the outer radius of the opening. After the closure engaging molded fiber object is wrapped around the opening, pressure may be applied to the closure engaging molded fiber object to ensure the adhesive bonds with the closure engaging molded fiber object and container. For example a die or dies may be arranged around the closure engaging molded fiber object and/or within the opening. The dies may exert a force which presses the closure engaging molded fiber object and the opening of the container together while the adhesive forms a bond.

In some examples the closure engaging molded fiber object comprises three threaded portions and two flexible portions, wherein flexible portions are located between and are joined to adjacent threaded portions, that is each flexible portion is joined to two threaded portions. However, as described in relation to FIGS. 1A and 1B the closure engaging molded fiber object may comprise more or fewer threaded portions and/or flexible portions.

In other examples a mechanical fixing may be used to attach the closure engaging molded fiber object to the container, for example as described in relation to FIGS. 1A, 1B and 2.

In some examples the method may comprise providing a liner within the container. The liner may be a liquid resistant lining, for example it may be water resistant or waterproof. The liner may be a film which is laminated to an interior surface of the container. The liner may be a coating applied to the interior surface of the container, for example by spraying. In other examples the liner may be a bag-like liner which is inserted into the container.

In some examples the method further comprises providing a sealing member on top of, within or around the opening of the container, for example as described in relation to FIG. 3. The sealing member may comprise a plastic, metal, rubber or some other material and when a closure is screwed on to the screw thread of the closure engaging molded fiber object, the sealing member may be urged towards an inside surface of the closure, thereby forming a seal to contain solids or fluids within the container. The sealing member may have a ring shape with a radius comparable (for example, substantially equal to) to the radius of the opening. The sealing member may also be provided with a lip or protrusion(s) to engage or align the sealing member with the opening.

The method may comprise bonding the sealing member to the liner. The sealing member may be bonded to the liner to provide a fluid resistant bond. For example the sealing member may be bonded to the liner using an adhesive or by welding (e.g. melting at least one of the liner and the sealing member such that they form a fluid resistant joint).

The present disclosure is described with reference to flow charts and/or block diagrams of the method, devices and systems according to examples of the present disclosure. Although the flow diagrams described above show a specific order of execution, the order of execution may differ from that which is depicted. Blocks described in relation to one flow chart may be combined with those of another flow chart.

While the method, apparatus and related aspects have been described with reference to certain examples, various modifications, changes, omissions, and substitutions can be made without departing from the spirit of the present disclosure. It is intended, therefore, that the method, apparatus and related aspects be limited only by the scope of the following claims and their equivalents. It should be noted that the above-mentioned examples illustrate rather than limit what is described herein, and that those skilled in the art will be able to design many alternative implementations without departing from the scope of the appended claims.

The word “comprising” does not exclude the presence of elements other than those listed in a claim, “a” or “an” does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the claims.

The features of any dependent claim may be combined with the features of any of the independent claims or other dependent claims.