Lid from a moulded fiber material, packaging unit comprising such lid, and method for manufacturing thereof

Abstract

The present invention relates to a lid 2 from a moulded fiber material, packaging unit comprising such lid and method for manufacturing the lid. The lid according to the invention comprising: - a cover part 4 having one or more clamping elements 6 and being configured for covering a packaging unit, and having a cover density; and - a breathing element 8 that is provided in the cover part, wherein the breathing element is configured to allow steam to pass through and leave the packaging unit, and wherein the breathing element comprises a breathing density that is smaller as compared to the cover density.

Description

[0001] The present invention relates to a lid from a moulded fiber material. These lids are used for packaging units such as cups, and other packaging units for containing, storing, transporting and / or displaying a range of products, such as food products including beverages. The lids are typically used for covering cups for holding (hot) beverages. The lids may also be used for other packaging units such as containers, carriers, covers, plates, cases, trays et cetera. The moulded fiber lid can be manufactured in a dry laid process with a "fluffy" pulp matrix.

[0002] Conventional lids are used in practice for covering cups and trays, for example. Conventional lids can be made from plastic material. To provide a more sustainable solution for covering a packaging unit with a product, conventional lids can also be provided from a mouldable fiber material.

[0003] A problem with conventional lids is the use thereof in combination with hot products, such as hot beverages in a cup. These hot products may form steam in the packaging unit and a consumer may be confronted with this hot steam. This can be unpleasant and may even be harmful for a consumer.

[0004] The present invention has for its object to obviate or at least reduce one or more of the above stated problems with conventional lids.

[0005] For this purpose, the present invention provides a lid from a moulded fiber material, wherein the lid according to the invention comprising: a cover part having one or more clamping elements and being configured for covering a packaging unit, and having a cover density; and a breathing element that is provided in the cover part, wherein the breathing element is configured to allow steam to pass through and leave the packaging unit, and wherein the breathing element comprises a breathing density that is smaller as compared to the cover density, wherein the cover density is the average density of the cover part excluding the breathing element and wherein the breathing density is the average density of the breathing element.

[0006] The lid according to the invention comprises a cover part that can cover the opening of a packaging unit. Such packaging unit typically relates to a cup for holding (hot) beverages. It will be understood that the lid may also be used for other packaging units that can hold products. The cover part is provided with clamping elements that can clamp the lid to a packaging unit. More specifically, the clamping elements enable a releasable clamping of the lid to a packaging unit, typically involving a clamping ring element engaging over the rim of a cup.

[0007] The invention further comprises a breathing element that is provided in the cover part. The breathing element allows steam to pass from the inside of the packaging unit, such as a cup, to the outer environment thereby leaving the packaging unit. This prevents a consumer from being confronted with an unpleasant experience and may even prevent injuries to the consumer as a result of the hot steam being trapped in the cup under the lid. Therefore, the lid of the invention provides a safety measure that is especially convenient when being applied to packaging units, such as a cup, containing hot beverages or other hot products.

[0008] According to the invention the breathing element is provided with a breathing density that is smaller as compared to the cover density. This cover density is the average density of the cover part excluding the breathing element. The breathing density is the average density of the breathing element. Providing the breathing element with a lower density enables steam to pass through the breathing element and leave the packaging unit. In presently preferred embodiments of the invention, the cover density is above 800 kg / m 3< , and preferably in the range of 800 kg / m 3< to 1200 kg / m 3< . The breathing density is preferably below 800 kg / m 3< , more preferably below 650 kg / m 3< , even more preferably below 550 kg / m 3< , even more preferably below 425 kg / m 3< , even more preferably below 350 kg / m 3< , and most preferably below 300 kg / m 3< .

[0009] As a further effect of the lid according to the present invention, spillage of the contents of the packaging unit, such as a cup, is prevented. This also contributes to providing a safety measure such that a consumer is not confronted with the hot spilled product(s) and may get injured.

[0010] The breathing element of the lid is provided with a thickness that is presently preferred to be in the range of 0.45 mm to 2.5 mm. Providing the breathing element with a certain thickness on one hand prevents undesired spillage of the contents of the packaging unit and on the other hand enables steam to pass through this breathing element.

[0011] As compared to an optionally provided regular drinking opening in a lid, the breathing element in a lid according to the present invention is provided with a thickness, while a drinking opening has no thickness and may result in spillage of the contents of the packaging unit. Furthermore, a regular drinking opening does not provide a controlled release of the steam that can be formed under the lid in the packaging unit. In presently preferred embodiments of the invention, the breathing element is provided to lids having no drinking opening and a consumer will remove the entire lid to enable access to the contents of the packaging unit.

[0012] In further preferred embodiments of the invention, the breathing element comprises a thickness that is in the range of 0.5 mm to 2.35 mm, more preferably in the range of 1.0 mm to 2.15 mm, and most preferably in the range of 1.5 mm to 2.05 mm. These further ranges have been proven to prevent spillage and enable steam to pass through the breathing element and leave the packaging unit such that the packaging unit and the lid can be safely used by a consumer.

[0013] The lid of the present invention can be manufactured in a dry laid process. In such process, the pulp matrix can be supplied as sheets or reels that can be fed into a hammer mill, or similar device also referred to as defibrator, that separates compressed rolls or sheets of the pulp into individual, loose fibers, which are then transported to the forming system that forms the lid.

[0014] Preparing and providing a mouldable fiber material typically involves providing an amount of fiber material. This fiber material may have different origin, such as wood and / or non-wood fiber material, optionally from a recycling process such as from recycled paper material. Alternatively, or in addition to such paper material, the fiber material may also comprise an amount of non-wood fiber material to which is also referred to as natural and / or alternative fibers. Such fibers may involve biomass fibers from plant origin, examples of which are described in WO 2021 / 145764 A1. After preparing a mouldable fiber material, the primary lid is formed in a mould. Such moulding involves the forming of the material into the desired shape of the primary lid. After the forming process the primary lids are typically dried, optionally involving an in-mould drying step.

[0015] In one of the presently preferred embodiments of the invention the mouldable pulp material comprises fiber material that optionally comprises an amount of non-wood fiber material. The non-wood fiber material is also referred to as natural and / or alternative fiber material. Providing an amount of these fibers provides a natural feel to the lid and / or improves the overall strength and stability of the lid. Such non-wood fibers may comprise fibers from different origin, specifically biomass fibers from plant origin. Examples of this biomass of plant origin are described in the aforementioned WO 2021 / 145764 A1.

[0016] In a presently preferred embodiment of the lid, the non-wood fiber material provides at least 5 wt% of the fiber material of the lid, preferably at least 10 wt%, preferably at least 50 wt%, even more preferably at least 80 wt%, even further more preferably at least 85 wt%, and most preferably at least 92.5 wt%. It was shown that lids can be manufactured effectively from the non-wood fiber material having such significant amounts of non-wood fiber material.

[0017] In a presently preferred embodiment of the invention the mouldable fiber material comprises an amount of non-wood fibers, wherein at least 80 percent of the fibers have a length above 1.1 mm, preferably a length above 1.2 mm. This provides a significant length increase of the fibers that are provided in the moulded pulp material as compared to most conventional lids. This results in an increased strength-weight ratio for the lid.

[0018] In a presently preferred embodiment of the invention, the mouldable fiber material comprises an amount of microfibrillated cellulose (MFC). In the context of the present invention this may also include nanofibrillar cellulose or cellulose nanofibers or nanocellulose. MFC preferably originates from cellulose raw material of plant origin. The use of MFC enhances the fiber-fiber bond strength and further improves the reinforcement effect in the matrix. In such embodiment of the invention, MFC provides improved barrier properties. Also, MFC may fill the gaps between the fibers and, therefore, has gas barrier properties, for instance an enhanced oxygen barrier. When MFC is modified, e.g. the carboxyl groups are replaced by a hydrophobic group, the modified MFC can enhance also the water vapor barrier. As a further advantage, a paper look and / or paper feel surface layer can be provided or improved. This paper look and / or paper feel surface layer contributes to the consumer's appreciation of the lid.

[0019] In a further preferred embodiment of the invention the mouldable fiber material comprises an amount of biodegradable polyester. Preferably, the biodegradable polyester in a lid is the constancy of size or dimensional stability.

[0020] In a further embodiment of the invention the biodegradable polyester in the mouldable fiber material comprises fibers that preferably have a length of above 1.2 mm. Providing fibers of the biodegradable polyester achieves a network of moulded and biodegradable polyester fibers in the moulded fiber product. This further improves the strength of the lid.

[0021] In one of the presently preferred embodiments of the invention the breathing element comprises a number of openings.

[0022] Providing a number of openings enables steam to leave the packaging unit such that a consumer can be provided with a hot beverage in a safe manner.

[0023] The number of openings is preferably in the range of 5 to 30, more preferably in the range of 10 to 25, and is most preferably in the range of 15 to 20. It will be understood that the number of openings can be adapted to the size of the packaging unit and the type of beverage or product in the packaging unit that is covered by the lid.

[0024] The openings in such embodiment of the invention are preferably configured in a grid or mesh. Such grid or mesh provides structure to the openings and further improves the controlled release of steam formed in the packaging unit. This further improves the overall safety of the lid and a packaging unit provided with such lid.

[0025] In presently preferred embodiments of the invention, the width or diameter of the openings is in the range of 0.2 mm to 1.0 mm, preferably in the range of 0.3 mm to 0.75 mm, and most preferably in the range of 0.45 mm to 0.6 mm.

[0026] Experiments have shown that these a size of the openings of the breathing element in the aforementioned ranges prevents spillage of the contents of the packaging unit while allowing steam which is formed inside the packaging unit to leave the packaging unit.

[0027] In a further preferred embodiment of the present invention the lid is manufactured from dry moulded fiber material.

[0028] Providing the lid from a dry moulded fiber material enables an efficient and effective manufacturing process resulting in a lid that is more sustainable as compared to conventional lids resulting from other manufacturing processes.

[0029] In a further preferred embodiment of the invention the breathing element comprises high-density parts and one or more low-density parts.

[0030] Providing high-density parts provides structure and stability to the breathing element(s). Providing low-density parts enables steam to pass through these parts and leave the packaging unit. In presently preferred embodiments of the invention, the high-density parts have a density above 600 kg / m 3< , preferably above 900 kg / m 3< , more preferably above 1050 kg / m 3< , and most preferably above 1150 kg / m 3< . Preferably, the one or more low-density parts have a density below 600 kg / m 3< , preferably below 425 kg / m 3< , more preferably below 350 kg / m 3< , and most preferably below 300 kg / m 3< .

[0031] Experiments have shown that the combination of densities for the high-density parts and the low-density parts in the aforementioned ranges provides a good prevention against spillage, while enabling steam to pass through the breathing element and leave the packaging unit.

[0032] The invention further relates to a packaging unit comprising a lid in an embodiment of the present invention.

[0033] Such packaging unit provides the same or similar effects and / or advantages as described in relation to the lid. The packaging unit advantageously relates to a drinking cup for a hot beverage that can be provided with a lid.

[0034] The invention further also relates to a method for manufacturing a lid from a moulded fiber material, wherein the method comprising the steps of: preparing a mouldable fiber material; forming the mouldable fiber material in a mould into a lid comprising: a cover part having one or more clamping elements and being configured for covering a packaging unit, wherein the cover part having a cover density; and a breathing element that is provided in the cover part, wherein the breathing element is configured to allow steam to pass through and leave the packaging unit, and wherein the breathing element comprises a breathing density that is smaller as compared to the cover density.

[0035] Such method provides the same or similar effects and / or advantages as described in relation to the lid and / or packaging unit provided therewith.

[0036] Optionally, the manufacturing method comprises providing mouldable fiber material involving one or more of the optional materials that are mentioned in relation to the lid. The method may further comprise the steps of providing one or more of the features that are described in relation to the lid, optionally including providing a number of openings in the breathing element and / or providing the mouldable fiber material from dry moulded fiber material.

[0037] Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which: Figures 1 A-C shows views of a lid according to a first embodiment of the invention; figure 2 A-C shows views of an alternative embodiment of a lid according to the present invention; figures 3 A-C shows views of a further alternative embodiment of a lid according to the present invention; figure 4 shows a packaging unit provided with a lid according to the present invention; figure 5 shows a manufacturing method of the lid according to the invention; and figure 6 shows a configuration of the moulds for moulding a lid according to figures 1 A-C.

[0038] Lid 2 (figures 1 A-C) comprises cover part 4 and clamping edge or clamping rim 6. Cover part 4 further comprises breathing element 8. In this illustrated embodiment, breathing element 8 comprises grid or mesh 10 having a relatively high density, and in this illustrated embodiment having a thickness d2. Breathing element 8 further comprises a number of low-density parts 12 having a thickness d1, wherein thickness d1 is substantially larger than thickness d2 of the more compressed high density parts 10.

[0039] In this illustrated embodiment, the density of grid or mesh 10 is above 800 kg / m 3< with a thickness d2 of about 0.5 mm. Low-density parts 12 have a density that is below 400 kg / m 3< with thickness d1 that is at least 1.5 mm, more preferably about 2 mm. Optionally, high-density parts 10 can be manufactured with an additional compressing step and / or this compressing can be integrated into the actual moulding. In this embodiment, clamping element 14 is provided as a ring-shaped element that is capable of engaging rim 66 of cup 64 (figure 4).

[0040] In an alternative embodiment, lid 22 comprises cover part 24 and clamping element 26 (figures 2A-C). Breathing element 28 comprises bottom part 30 that in the illustrated embodiment substantially fills entire breathing element 28. Bottom part 30 is provided with thickness d3. Bottom part 30 with thickness d3 remains somewhat "fluffy" to allow steam to pass through breathing element 28 and also to prevent spillage. In the illustrated embodiment thickness d3 is in the range of 1.5 mm to 3.0 mm. It will be understood that thickness d3 will preferably be designed in relation to the specific packaging unit, lid material and / or product type.

[0041] In a further alternative embodiment, lid 42 (figures 3 A-C) comprises cover part 44 with clamping element 46 shaped as a clamping ring. Cover part 44 comprises breathing element 48 with a number of openings 50. Openings 50 are relatively small having diameter D. In the illustrated embodiment, about fifteen openings 50 are provided that each have a diameter of about 0.5 mm. These small size holes prevent spillage and allow steam to leave the packaging unit. It will be understood that also in this case the exact diameter D of openings 50 may depend on material characteristics, type of packaging unit and product type.

[0042] Lids 2, 22, 42 can be applied to cup 64 having rim 66 (figure 4). Packaging unit 64 with lid 2, 22, 42 forms assembly 62 of a packaging unit with lid 2, 22, 42.

[0043] Manufacturing process 102 (figure 5) comprises preparation step 104 wherein a fiber material is prepared. Preparation step 104 may involve applying and / or mixing wood fiber material and / or non-wood material such as alternative fibers. Wood material may involve so-called virgin fibers and / or fibers from recycled paper material, for example. Prepared fiber material 106 is then provided to forming step 108 wherein lid 2, 22, 42 is formed / moulded, preferably already including breathing element 8, 28, 48. Optionally, a separate step is included for providing breathing element 8, 28, 48. Lid 2, 22, 42 is then optionally further processed in further processing step 112 resulting in end-product 2, 22, 42.

[0044] Lid 2, 22, 42 is then applied in application step 114 to a packaging unit, such as a cup filled with a beverage or other product.

[0045] Optionally, packaging unit 2, 22 is provided with alternative fiber material having fibres that preferably remain visible for a consumer. This fiber material may relate to wood and non-wood fibres, such as the alternative fibres that are mentioned earlier. In some embodiments, the illustrated lid 2, 22, 42 comprises a moulded fiber material that is provided with an amount of MFC and / or biodegradable aliphatic polyester, such as PLA and / or PHBT. Optionally, an amount of calcium carbonate is applied.

[0046] Optionally, further additional materials are being used, for example Xerolex (or BIM DS2801 as example of a dry strength agent) and / or AKD.

[0047] Mould set 202 (figure 6) comprises top mould 204 and bottom mould 206. Mould set 202 is preferably used in forming step 108 of manufacturing process 102. In the illustrated embodiment, in forming step 108, volume 208 between moulds 204, 206 is filled with prepared fiber material 106 to form lid 2. It will be understood that other shapes can also be envisaged in accordance with the present invention. Mould set 202 can be used in the manufacturing of lid 2, 22, 42. Forming step 208 is optionally performed at a forming temperature in the range of 90°C to 220°C, preferably in the range of 110°C to 180°C, even more preferably in the range of 125°C to 165°C, and most preferably at a temperature of about 150°C. Forming pressure may be in the range of 0.5 MPa to 150 MPa, more preferably in the range of 0.8 MPa to 25 MPa, and even more preferably in the range of 0.95 MPa to 10 MPa. Forming time with closed mould set 202 is optionally in the range of 0.1 seconds to 10 seconds, more preferably in the range of 0.25 seconds to 4.5 seconds, and most preferably in the range of 0.45 seconds to 2.5 seconds. For example, mould set 202, or any other suitable mould set, can be used in the manufacturing process at a forming temperature of 155°C, a forming pressure of 4.5 MPa, and a holding time of 1.0 seconds. It will be understood that other combinations of process conditions are also possible, for example depending on the specific materials and / or lid designs that are applied.

[0048] The present invention is by no means limited to the above-described preferred embodiments thereof. The rights sought are defined by the following claims within the scope of which many modifications can be envisaged.

Claims

1. Lid from a moulded fiber material comprising: - a cover part having one or more clamping elements and being configured for covering a packaging unit, and having a cover density; and - a breathing element that is provided in the cover part, wherein the breathing element is configured to allow steam to pass through and leave the packaging unit, and wherein the breathing element comprises a breathing density that is smaller as compared to the cover density, wherein the cover density is the average density of the cover part excluding the breathing element and wherein the breathing density is the average density of the breathing element.

2. Lid according to claim 1, wherein the breathing density is below 800 kg / m3, preferably below 650 kg / m3, more preferably below 550 kg / m3, even more preferably below 425 kg / m3, even more preferably below 350 kg / m3, and most preferably below 300 kg / m3.

3. Lid according to claim 1 or 2, wherein the breathing element comprises a thickness in the range of 0.45 mm to 2.5 mm, preferably in the range of 0.5 mm to 2.35 mm, more preferably in the range of 1.0 mm to 2.15 mm, and most preferably in the range of 1.5 mm to 2.05 mm.

4. Lid according to claim 1, 2 or 3, wherein the breathing element comprises a number of openings.

5. Lid according to the foregoing claim, wherein the number of openings is in the range of 5 to 30, preferably in the range of 10 to 25, and most preferably in the range of 15 to 20.

6. Lid according to the foregoing claims 4 or 5, wherein the openings are configured in a grid or mesh.

7. Lid according to claim 4, 5 or 6, wherein the width or diameter of the openings is in the range of 0.2 mm to 1.0 mm, preferably in the range of 0.3 mm to 0.75 mm, and most preferably in the range of 0.45 mm to 0.6 mm.

8. Lid according to any of the foregoing claims, wherein the lid is manufactured from dry moulded fiber material.

9. Lid according to any of the foregoing claims, wherein the breathing element comprises high-density parts and one or more low-density parts.

10. Lid according to the foregoing claim, wherein the high-density parts have a density above 600 kg / m3, preferably above 900 kg / m3, more preferably above 1050 kg / m3, and most preferably above 1150 kg / m3.

11. Lid according to the foregoing claims 9 or 10, wherein the one or more low-density parts have a density below 600 kg / m3, preferably below 425 kg / m3, more preferably below 350 kg / m3, and most preferably below 300 kg / m3.

12. Packaging unit comprising a lid according to any of the foregoing claims.

13. Method for manufacturing a lid from a moulded fiber material, wherein the method comprising the steps of: - preparing a mouldable fiber material; - forming the mouldable fiber material in a mould into a lid comprising: - a cover part having one or more clamping elements and being configured for covering a packaging unit, and having a cover density; and - a breathing element that is provided in the cover part, wherein the breathing element is configured to allow steam to pass through and leave the packaging unit, and wherein the breathing element comprises a breathing density that is smaller as compared to the cover density.

14. Method according to the foregoing claim, wherein the mouldable fiber material is provided from dry moulded fiber material.

15. Method according to the foregoing claims 13 or 14, further comprising the step of providing a number of openings in the breathing element.

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