The present invention relates to a method for manufacturing a foamed packaging unit. More specifically, the packaging unit is made from a moulded fiber material and can be used for products like eggs, and similar products like kiwis and tomatoes for example.

Conventional manufacturing methods for packaging units start with preparing a moulded pulp originating from (recycled) paper material. After preparing the moulded pulp this moulded pulp material is provided to a mould to manufacture a raw packaging unit. Thereafter, the raw packaging unit is released from the mould and the packaging unit is dried. Especially the post- forming process involving a drying operation requires a large amount of energy. This results in high manufacturing costs for conventional packaging units.

The present invention has for its object to obviate or at least reduce the above staled problems and to provide a cost effective manufacturing method for packaging units.

The present invention provides for this purpose a method for manufacturing a foamed packaging unit that comprises the steps of:

- preparing a foamed mouldable fiber material comprising a fiber material and a foaming agent;

- moulding a raw packaging unit from the foamed mouldable fiber material, wherein the solid content of the raw packaging unit is above 35% by weight; and

- in-mould drying the raw packaging unit to the foamed packaging unit.

According to the manufacturing method according to the invention the foamed moulded fiber material comprises a moulded pulp with fiber material and a foaming agent. The fiber material may relate to conventional mouldable pulp material originating from recycled paper or any other origin. The mouldable pulp material is foamed with the aid of the foaming agent. This provides a foamed mouldable pulp that can be used for forming a packaging unit in the manufacturing process according to the present invention.

After moulding a raw packaging unit from the foamed moulded fiber material a drying process step is performed. The manufacturing process according to the invention with foamed moulded pulp material results in a raw packaging unit having a much lower solid content after forming and before drying as compared to conventional manufacturing process. Therefore, the drying step in a manufacturing method according to the present invention can be performed more effectively. More specifically, the increase of solid content after forming in the method according to the invention significantly reduces the amount of water that needs to be removed in the drying operation, thereby significantly reducing the energy usage in the drying operation resulting in a significantly reduction of the energy costs in the manufacturing method. A comparison with conventional methods showed that the manufacturing method according to the invention provides a (foamed) raw packing unit from the forming/moulding step that has a solid content that is 4% higher and requires 20% less drying energy and thus expenses as compared to a conventional manufacturing method. Therefore, this significantly improves the cost effective manufacturing of packaging units from (foamed) moulded fiber material.

The in-mould drying step can be performed in the same moulds that are used in the moulding step or can be performed in specific moulds for the drying step. It is also possible to perform the drying process in sub-steps with the use of a number of drying moulds for one or more of these sub-steps. This may further improve product quality of the end product.

As a further effect the foamed packaging unit resulting from the manufacturing method according to the present invention is more homogeneous as compared to conventional packaging units. Also, the surface roughness is significantly decreased as compared to such conventional packaging units. This improves the haptic appearance of the packaging unit as well as the visual appearance that will be appreciated by consumers. Furthermore, the weight of the final product in relation to its strength is also improved. This enables a cost effective manufacturing of a packaging unit from foamed moulded fiber material.

As a further effect the use of denesting additives, such as paraffin, is prevented or reduced. This is achieved by the reduction in surface roughness such that denesting of the manufactured product is easier.

Due to the use of foamed mouldable fiber material for forming or moulding the packaging units the strength of the packaging unit can be achieved with less material, more specifically less weight. This reduces the amount of raw material that is required, such as recycled paper or virgin pulp. This further improves the manufacturing method.

In addition to the decreased surface roughness and improved homogeneity of the resulting packaging unit, new designs can be developed having a smaller stacking pitch such that a stack of packaging units may comprise a higher number of packaging units as compared to conventional designs from conventional packaging units. This improves the handling efficiency of the packaging units. This further improves the overall flexibility and freedom in design of packaging units. Also the printing possibilities can be improved by the roughness reduction.

As an even further effect the foamed moulded fiber of the packaging unit can be produced achieving an improved heating insulation, thereby improving protection/insulating the products that are provided in the packaging unit against (varying) outside conditions. This improves keeping the product in the packaging unit that is manufactured according to the present invention.

As a further effect of manufacturing a foamed packaging unit according to one of the embodiments of the invention is that the packaging unit can be provided with a lower carbon footprint. Depending on the application the reduction can be 60-80% as compared to comparable packaging units made of plastic or another material.

According to one of the embodiments according to the present invention, in the preparation step for the foamed moulded fiber material, the fiber material with the consistency of 1-4% (10-40 kg/in ³ ) is provided with 0.2-3% surfactant foaming agent and provided to a foam generator or aerator. For example, such generator uses a high speed rotor and provides an additional supply of air to achieve a foamed moulded fiber material with a density in a range of 300-900 kg/m\ preferably in a range of 400-600 kg/m ³ . In a presently preferred embodiment the foamed moulded fiber material is transferred to the moulding step as soon as possible to achieve a high quality end product. In experiments it was shown that in some of the preferred embodiments the foamed material had a lifespan that was relatively short to achieve maximum product quality. This lifespan that is expressed as the half-life time for the foamed pulp is in the range of 1-60 seconds, preferably in the range of 2-30 seconds. The foamed material comprises at to about 70% of air and a minimum amount of water. Especially the low amount of water in combination with the relatively short half-life time of the foamed material achieves a higher solid content. Experiments have shown an increase in solid content after the moulding-forming of the raw material product in the range of 1-6% eventually leading to a reduction in required drying energy in the range of 10- 25%. In these experiments, the products, specifically egg-cases, are produced with less material (about 10% less) and having a similar bending stiffness, three points bending stiffness of the final product as compared to conventional manufacturing methods. The homogeneity of the material is also improved, thereby contributing to a reduction of the surface roughness due to an improved distribution of fibers over the surface. As a further effect the overall production capacity can be increased with up to 50%.

In a presently preferred embodiment according to the invention the foaming agent comprises SLES, SDS and/or ALS and/or other detergentia/surfactants.

Providing SLES (sodium lauryl ether sulphate), SDS (sodium lauryl sulphate and/or sodium dodecyl sulphate) and/or ALS (ammonium lauryl sulphate) to the mouldable fiber pulp achieves a foamed mouldable fiber pulp that can be effectively used for forming a packaging unit of a foamed moulded fiber material.

In a presently preferred embodiment of the invention preparing a foamed moulded fiber material comprises adding one or more additives.

Adding one or more additives in the manufacturing process the product characteristics can be improved. In one of the presently preferred embodiments the additives comprise a dewatering polymer, most preferably a polyacrylamide. In addition thereto, or as an alternative therefor, other additives can be added, such as alkyl ketene dimer (AKD). The addition of the additives can be done in the preparation step when preparing the foam material and alternatively or in addition thereto in a preliminary supply step of one or more of the raw materials.

Optionally, the one or more additives comprise solid particles and/or filaments. This may further improve the product properties. In addition, this enables achieving specific product characteristics that are aimed at a specific purpose. This improves the overall flexibility of the manufacturing method according to the invention.

In further preferred embodiments of the invention the one or more additives comprise one or more of polylactic Acid (PLA), polyhydroxybutyrate (PHB), polyglycolic acid (PGA), polyhydroxyalkanoate (PHA) or combinations thereof. Also, polybulviene succinate (PBS) can be added. Preferably, the additives are recyclable and biodegradable and safe to use for food material, especially food packaging. This achieves a recyclable product that is safe to use in food packaging.

Optionally, the moulded pulp may comprise additional components of additives, such as wet strength agent, dry strength agent, dye/pigment, starch derivatives, releasing agent such as calcium stearate.

As a further effect of providing additives, the water resistance of the end product can be improved and also the possibilities for use in a refrigerator with a low temperature and relatively high humidity can be achieved. In addition, other resistances can be improved.

Material for the packaging unit according to the invention may comprise recycled fiber material and/or so-called virgin fiber material.

Preferably, the material of the packaging unit comprises a recycled fiber material including raw material originating from (recycled) paper and/or carton and/or similar waste streams. This recycled fiber material can be used as alternative to so-called virgin fiber material and/or in combination therewith. The use of recycled fiber material may contribute to a more sustainable manufacturing process.

In a further preferred embodiment according to the present invention the material comprises natural fibers of non-wood lignocellulosic biomass.

By providing lignocellulosic biomass from other resources as the conventional paper recycling, an alternative source for the material for the packaging unit of moulded pulp is provided.

This improves the availability of raw (starting) material when manufacturing packaging units according to the invention. In addition, the use of this biomass provides additional visual effects that may provide the packaging unit with a more natural feel and look, and, in addition, may improve the sustainability of the packaging unit according to the present invention.

In a presently preferred embodiment the moulded pulp may comprise at least 10% by weight non-wood lignocellulosic biomass, preferably at least 50% by weight, more preferably at least 80% by weight, even more preferably at least 85% by weight, and most preferably at least

92.5% by weight non-wood lignocellulosic biomass. Preferably, the lignocellulosic biomass comprises biomass originating from plants of the family of Poaceae Family including grass type of plants, including grass and barley, mais, rise, weed, oaths, rye, wheat grass, bamboo, sugar cane, rape seed, straw, grape seeds, other cereals, etcetera. Especially the use of so-called nature grass provides good results on manufacturing packaging units such as packages. Such nature grass may originate from a natural landscape, for example. This material shows effective manufacturing possibilities in combination with providing the packaging unit with a sustainable appearance to the consumer. The use of this alternative raw material as a foamed moulded fiber material provides additional possibilities to improve the packaging units.

Preferably, the protein content of the biomass is between 0 to 5%, more preferably between 0 to 4%, preferably below 3%, more preferably below 2% and most preferably below

1.75% of dry weight of the biomass. Removing protein from lignocellulosic biomass is known per se, like from the patent publication WO 2012/023848 Al to Danvos B .V. The combination of using this biomass raw material in combination with, or as an alternative to, moulded pulp originating from paper and/or paperboard provides further possibilities for the use of different raw materials, and improves the "green'Vsustainable appearance of the resulting packaging units.

Foaming such alternative (non-wood) fiber material provides similar effects and advantages as described for the (recycled) paper material.

In a presently preferred embodiment of the invention the method further comprises the step of transferring the raw packaging unit from the mould to a drying mould.

As was mentioned earlier, the drying operation can be performed in a specific drying mould. This further improves the capacity of the production facility and/or enables a dedicated mould for the drying operation. As also mentioned, several specific moulds can be used in series in different sub-steps of the drying process.

Preferably, the solid content of the fiber material after forming is above 36% by weight, preferably above 37% by weight, more preferably above 38% by weight, and most preferably above 39% by weight. It is shown that with the use of a foamed mouldable fiber pulp in the manufacturing process a higher solid content of the fiber material in the packaging unit after forming can be achieved, above 35% by weight and even higher. This significantly reduces the requirements for the drying operation as described above. The solid content of the raw packaging is optionally also referred to as % dryness.

The foamed mould fiber material comprises a volume percentage of preferably more than 50% air, preferably more than 60%, and is most preferably in the range of 60-75%. In the context of the invention air relates to the gas that is provided and/or used when foaming the moulded pulp material. This high volume of air improves the aforementioned effects in relation to the foamed moulded fiber material. In a presently preferred embodiment according to the present invention moulded pulp has before forming a consistency, relating to the fiber-water ratio, of above 1.0% by weight, preferably above 1.3% by weight, more preferably above 2.0% by weight, and most preferably above 2.5% by weight.

Conventional consistency ranges are below 1.0% by weight. Increasing this consistency weight ratio provides a stronger product after forming. This enables a reduction in the weight of the packaging unit having similar strength, for example. Preferably, the label is printed and contains information about the packed product.

In a further preferred embodiment according to the present invention the drying step further comprises the in-mould providing of a label.

By in-mould providing a label a central labelling step can be omitted from the

manufacturing process. In this embodiment of the invention a label is provided in the drying mould preferably. In the drying step the label attaches to the raw product and after drying has ended, the final end product is already provided with a label. In one of the preferred embodiment the label comprises one or more of PLA, PBS, PHB, PGA, PHA. This improves recycling possibilities for the manufacture packaging unit and/or improves the attachment of the label to the product.

The present invention further also relates to packaging unit made of foamed moulded pulp for products like eggs, comprising:

- a carrier part having a length, a width and a depth; and

- one or more product compartments that are provided in the carrier and are configured for receiving a product,

wherein the foamed moulded pulp comprises a fiber material, a foaming agent and one or more additives.

Such packaging unit provides the same effects and advantages as described with respect to the manufacturing method. In presently preferred embodiments of the packaging unit one or more of the (optional) manufacturing steps that are already described are performed to manufacture the packaging unit according to one of the preferred embodiments thereof. Also, the packaging unit according to the invention can be manufactured with both conventional drying steps and/or in- mould drying steps.

Preferably the one or more additives comprise one or more of PLA, PBS, PHB, PGA,

PHA. This achieves the aforementioned advantages and effects. This also applies in further preferred embodiments wherein the additives comprise a dewatering polymer, such as a polyacrvlamide, specific solid particles and/or filaments, the filming agent comprising: SLES, SDS and/or ALS, the use of recycled fiber material, optionally involving natural fibers of non-wood lignocellulosic biomass. In a further preferred embodiment according to the present invention the packaging unit further comprises a cover part having a length, a width and a depth.

By providing a cover part, the combination of the carrier part and cover part provides a packaging unit that protects substantially the whole product, such as eggs.

Preferably, the packaging unit comprises a hinge from foamed moulded fiber material hingedly connecting the carrier part and the cover part. This provides a packaging unit with a bottom part and a cover part, and enabling transport and display of products without damaging the products. This is especially relevant in case of vulnerable products like eggs. Preferably, the cover part is hingedly connected to the bottom part on the rear side thereof. It is shown that the hinge manufactured from foamed moulded fiber material is capable of performing the operation of opening and closing the cover part from the bottom part.

Preferably, on the front side of the packaging unit a lock is provided comprising a first locking element on a bottom part and an opening in a cover part that is configured for receiving the first locking element. By locking the cover part and a bottom part of the front surface the packaging unit can be closed. Preferably, the bottom part is provided with a protrusion shaped as an edge or a notch acting as first locking element. Such protrusion can be provided directly by the bottom part or a separate closing flap that is hingedly connected to the bottom part. It will be understood that other configurations according to the invention would also be conceivable.

Furthermore, the foamed moulded fiber material for the packaging unit according to the present invention showed good manufacturing possibilities such that a carrier and/or cover part can be provided that has a length, a width and a substantial depth of preferably 3 cm or more, preferably 4 cm or more, and even more preferably 5 cm or more.

According to a further preferred embodiment of the packaging unit according to the invention, the packaging unit is one or more of an egg package, cup carrier, fast food packaging unit, bottle dividers, food containers for ready meals, and protective packaging unit.

Such packaging units are preferably substantially made of foamed moulded fiber material and benefit from the associated effects that have been described earlier. Egg packaging may relate to packaging units, preferably a bottom part with a cover part that are hingedly connected, capable of transporting and displaying eggs. A cup carrier can be used to carry one or more cups, such as coffee cups. Fast food packaging units may relate to containers for holding hamburgers and french fries, for example. Bottle dividers protect bottles and the use of foamed moulded fiber material improves the protection of the bottles and especially the crown corks thereof. Food containers for ready meals from foamed moulded fiber improve storage, transport and presentation of food stuff to a consumer, wherein the container is preferably laminated with a barrier film, such as a biofilm or polyolefin film, and is further preferably made of so-called virgin fiber material to prevent migration of undesired components from the material towards the food. This may also relate to coffee cups, for example. Protective packaging units may relate to packaging units carrying electronic components, for example.

Further advantages, features and details of the invention are illustrated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:

- figure 1 shows a schematic overview of the manufacturing method according to the present invention;

- figure 2 shows a packaging unit produced by the manufacturing method of figure 1 comprising natural fibers; and

- figures 3-4 show a further alternative packaging unit of the invention.

Manufacturing process 2 (figure 1) starts with collecting the fiber material 4. Additives 6 are prepared and both the raw fiber material and the additives are provided in a foam chamber to start preparing the foamed product 8. The foamed material is provided to the mould(s) for the forming process 10. After the foaming process has ended a further processing step is performed. This may involve transferring 12 of the raw products to the drying process 14, optionally involving in-mould drying or conventional drying. It is also possible to perform the drying step in the forming moulds. After the drying process has ended the end product is released 16.

Packaging unit 102 (Figure 2) comprises bottom part 104 with front surface 106, two side surfaces 108, back side 110, and bottom side 1 12. In the illustrated embodiment, cover part 114 is hingedly connected with hinge 1 16 to bottom part 104 to allow cover part 114 to move relatively to bottom part 4 between an open and a closed position. Cover part 114 further comprises front surface 118, two side surfaces 120, back side surface 122 and top surface 124.

On the inside of bottom part 104 product receiving compartments 126 are provided having contours matching at least partially the outer contours of the products, like eggs, kiwis and tomatoes, for example. Support cones 128 are provided to add stability and strength to packaging unit 102. Lock 130 comprises opening 132 in cover part 1 14 and cam 134 of bottom part 104.

Optionally, packaging unit 102 is provided with a label.

Reinforcing elements comprise groove 138 with starting position 140 at top 124 of cover part 114 and ending position 142 at front surface 118 of cover part 114. Alternative reinforcing elements that may be applied in combination with grooves 138 comprise strengthening rods, rims and/or protrusions.

In the illustrated embodiment package 102 is optionally made from foamed moulded fiber material containing a substantial amount of grass fibers, for example 50%, or 80%, or 90% or 95%. It will be understood that packaging unit 102 can also be manufactured from conventional moulded fiber material, for example originating from recycled paper. Fibers 148, in the illustrated embodiment optionally grass fibers, are provided in the foamed packaging material. After drying, some of the (grass) fibers 150 may protrude from a package surface, including the surface of compartment 126, that protrude to such an extent that separate (grass) fibers can be distinguished by sight and/or touch. In compartment 126 protruding fibers 150 provide a cushioning effect that may further contribute to the reduction of product damage.

These longer (grass) fibers 148, 150 have a length of about 25 mm. The longer (grass) fibers 148, 150 have a length such that the fibers are able to float on a foamed fiber pulp or pulp mix during manufacturing, which enables that during moulding these long fibers are positioned at the package surface. These protruding fibers 50 even more improve the appealing effect of the package 102. Fibers 150 protrude even more from a package inside surface also because that inside surface is determined by the suction side of a mould. This suction side of a mould is a well known concept in manufacturing a moulded fiber food packaging.

When manufacturing packaging unit 102, a fiber pulp for a moulding process from natural (grass) fibers is contained in a pulp container also referred to as storage tank and also known as thick stock tank. The process of moulding a moulded fiber package is not described here since this is known per se. Such a process of moulding a moulded fiber package is fed with the fiber pulp mix from the pulp container.

According to the invention, the foamed pulp comprises lignocellulosic biomass not originating from wood, wherein in the illustrated embodiment the lignocellulosic biomass contains between 0 to 2% protein in dry weight.

The method comprises pre-processing of the lignocellulosic biomass involving a number of steps. Depending on the product all steps are required or, alternatively only some steps need to be performed optionally with further steps. This pre-processing may be done on site or (partly) elsewhere. When the lignocellulosic biomass is pre-processed elsewhere, the lignocellulosic biomass fibers may be added directly to the pulp mix. Here, the pre-processing comprises soaking the lignocellulosic biomass in water for a soaking period of at least 1 day preferably at least 2 days. Here, the pre-processing comprises cutting the lignocellulosic biomass, preferably before the soaking, for obtaining visible lignocellulosic biomass fibers having a length such that the visible lignocellulosic biomass fibers may surface on the fiber pulp mix.

The pre-processing in the illustrated embodiment comprises refining the visible lignocellulosic biomass fibers for facilitating interaction between the fiber pulp and the visible lignocellulosic biomass fibers in the pulp mix.

The refining is performed in a refining device (not shown) comprising a number of refiner discs arranged at a mutual disc distance. The degree of refining the visible lignocellulosic biomass fibers is set by adjusting the disc distance between 0.2 and 1.5 mm. The refining of the visible lignocellulosic biomass fibers is done at a concentration of between 10 kg to 75 kg, preferably about 25 kg visible lignocellulosic biomass fibers in dry weight, per 1000 litre of water. An example of such a refiner is a Sprout Waldron disc refiner.

Before providing the lignocellulosic biomass, the lignocellulosic biomass may be processed for removing protein from the lignocellulosic biomass such that the lignocellulosic biomass contains between 0 to 2% protein in dry weight. This process is not shown here.

Optionally, in the manufacturing process colouring agents/pigments can be added. Also, additional components can be added, for example including dewatering polymers.

The fiber material is provided with foaming agent and a foamed mouldable fiber material is provided. Next, the forming process forms form this material a packaging unit. After forming, a drying operation is performed to produce the packaging unit from foamed moulded fiber material.

Hybrid pack 202 (figures 3-4) constitutes a different design for a foamed packaging unit and comprises first packaging unit 204 and second packaging unit 206 according to the invention of a foamed moulded fiber material. First and second packaging units 204, 206 are connected with bridging part 208. Bottom part 210 comprises front surface 212, two side surfaces 214, back side 215. and bottom side 216. Cover part 218 is hingedly connected to bottom part 210 and comprises front surface 220, two side surfaces 222. back side surface 224 and top surface 226. In the illustrated embodiment packaging units 204, 206 are provided with label 228 that is provided with top surface 30 on which text 32 is printed. In this illustrated embodiment label 228 is provided during the in-mould drying process by providing the mould with label 228. Label 228 has front surface 234, and extended part 236 for front side 234. Extended part 236 and front surface 234 are connected with folding line 238. Edge 240 defines the transition between top surface 230 and front surface 234. Packaging units 204, 206 are provided with indent 242 having an egg-shape 244. In the illustrated embodiments label 228 is provided with corresponding cut-out 246.

Alternative packaging unit 202 is manufactured from a foamed moulded fiber material comprising fiber material and a foaming agent including the hinge connecting bottom part 210 with cover part 218. It will be understood that different designs and dimensions of packaging unit 202 can be envisaged according to the invention.

In the illustrated embodiment, on the inside of bottom part 210 (figure 4) compartments 248 are provided having contours matching at least partially the outer contours of eggs P. Support cones 250 are provided to add stability and strength to packaging units 204, 206. Lip 252 is hingedly connected to front surface 212 of bottom part 210 and is provided with cut-out 254. Along the edge of cut-out 54 there is provided a support edge 256 for distributing loads. In addition, a support nock 258 is provided. Cover part 218 and bottom part 210 are hingedly connected via hinge 260 that is also provided of the foamed moulded fiber material. Cover part 218 is provided with a window opening 262 through which the back side 264 of label 228 is visible. In the illustrated embodiment back side 264 of label 228 is provided with text and/or images 266. Alternatively, label 228 is provided with transparent material for window opening 262.

Front 220 of bottom part 210 is provided with edge, protrusion, or projection 270 that fits in opening 268 that is provided in front surface 234 of label 228 together providing lock 272 that can be provided in the label and/or the moulded fiber material.

When manufacturing a packaging unit, such as packaging unit 102 and hybrid pack 202, a moulded pulp from recycled paper, cardboard etc. is provided as a moulded pulp. A foaming agent is added to produce a foamed mouldable fiber material. Optionally, one or more of the additives that were mentioned earlier are included. With a (vacuum) moulding device, packaging unit 202 is formed from the foamed mouldable fiber material. After forming, packaging unit 202 is dried to produce the packaging unit, such as hybrid pack 202, made of foamed moulded fiber material.

It will be understood that different designs for the packaging unit are possible according to the invention. Also, the use of different raw materials for different designs would be possible. For example, hybrid pack 202 can be manufactured from lignocellulosic biomass and packaging unit 102 from a moulded fiber origination from recycled paper and cardboard.

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 are possible. For example, the packaging unit according can be applied to eggs and other vulnerable food and non-food products as well as to other products. Non-limiting examples of products include eggs, vegetables, fruit, electronic products such as DVD players, displays, mobile phones, tablets etc..