A beverage capsule comprising a barrier liner attached to a pulp body

Abstract

The present invention relates to a capsule (1) for beverage preparation, comprising a cup-shaped body (2) of molded cellulose pulp and a closing membrane (5) attached to the body (2). The capsule further comprises a multilayer polymer liner (3) attached to the inner surface of the cellulose pulp body (2), the liner comprising: (i) an outermost polymer layer (7) having an elongation at break of between 10% and 800%, a melt flow rate (MFR) between 2 and 4, and a melting point temperature below 80°C; (ii) a first connecting layer (8); (iii) a barrier layer (9); (iv) a second connecting layer (10); and (v) an innermost polymer layer (11) comprising a biodegradable polymer, the innermost layer having a thickness between 10 and 100 µm, and having an elongation at break of between 10% and 1000%, a melt flow rate (MFR) between 4 and 10, and a melting point temperature between 110°C and 180°C.

Description

Technical Field

[0001] The present invention relates to a capsule for beverage preparation, which is recyclable in a paper recycling stream and comprises an outer body made of compressed cellulose pulp, the outer body being reinforced with a gas and moisture barrier liner tightly adhered to the pulp body. Prior Technology

[0002] Capsules and pouches used in beverage preparation machines are well-known. They represent a convenient and clean method for preparing edible beverages. In the following description, the common term "capsule" will be used, encompassing single-use packaging for preparing beverages for human consumption by insertion into a beverage preparation machine adapted to inject fluid (preferably hot water) into the package for mixing with its contained ingredients. Examples of such beverage packaging are not limited to rigid capsules, but also include rigid, semi-rigid, or flexible pouches, pads, various types of boxes, and even pouch-type containers.

[0003] Generally, these capsules are made of plastics such as polyolefins or biodegradable plastics, which are usually injection- or thermoformed to obtain a cup, which is then filled with ingredients and sealed with a membrane to close the capsule tightly with gas and moisture.

[0004] Recently, there has been an increasing awareness of the environmental impact of plastic packaging and a need for new packaging solutions that are biodegradable or recyclable after use, and specifically, that allow used packaging to be compostable or recycled in a recycling stream suitable for paper or cardboard ("paper recycling stream").

[0005] Recently, beverage preparation capsules have been developed, which are made from cellulose fiber pulp (or "cellulose pulp" or "pulp"), which is molded to form a rigid or semi-rigid capsule cup-shaped body. The cup-shaped body defines a compartment containing beverage precursor ingredients (such as roasted and ground coffee). The cup-shaped body is closed by attaching (e.g., by sealing) a wall (e.g., a membrane or film) to it.

[0006] To ensure the freshness of beverage precursor components throughout the capsule's shelf life, especially during storage and use, oxygen and moisture barrier materials need to be incorporated into the cellulose pulp (and the closing film). These barrier materials typically take the form of a so-called "barrier liner," which is a single or multilayer film adhered to the inner surface of the pulp matrix (i.e., the surface facing the components). The liner is bonded to the pulp by thermoforming both the liner and the pulp in a mold.

[0007] During beverage preparation, a capsule is inserted into the brewing chamber of a beverage preparation machine. This machine includes a water injection component, such as a set of blades designed to pierce the thickness of the capsule body and inject water into it under pressure. The water mixes with the components of the resulting beverage. As the water pressure increases and reaches a certain level, the closure membrane deflects outward and pierces the piercing component of the beverage machine. When the membrane is pierced, the beverage flows out of the capsule (towards the cup).

[0008] WO2021 / 145764 A1 discloses a container comprising a molded fibrous matrix and providing a biodegradable multilayer on its inner surface. The biodegradable multilayer has a five-layer structure, wherein the inner and outer cladding layers comprise biodegradable aliphatic polyesters and are integrated into an intermediate layer (a functional barrier layer comprising PVOH). A first intermediate layer and a second intermediate layer are provided for connecting and / or sealing adjacent layers with biodegradable materials.

[0009] WO2015 / 082982 A1 proposes a capsule comprising a body made of paper material and a plastic laminate made of PLA / PVOH / PLA.

[0010] WO2020 / 114995 A2 discloses a capsule comprising a body made of cellulose (paper) and a plastic laminate made of PLA / PVOH / PLA, the plastic laminate having a defined tensile value between 2% and 20% of the entire laminate upon rupture.

[0011] The beverage preparation using pulp-type capsules, as described above, is a promising approach to reducing the environmental footprint of packaging. However, a technical drawback arises during the piercing of the capsule body by the water-injection blades of the machine. When the water-injection blades pierce the capsule pulp body, these blades grip the pulp material, and as they move toward the interior of the capsule, the mass of the pulp attached to the blades causes the liner to delaminate from the pulp and pushes the liner without piercing it. This delamination effect is amplified by the liner's higher elasticity than the pulp. As a result, the liner is pulled toward the interior of the capsule without being pierced, and when water injection begins, no water enters the capsule compartment: the capsule is blocked and no beverage comes out.

[0012] The purpose of this invention is to provide a technical solution to the delamination challenge mentioned above in beverage capsules made of molded pulp and having barrier linings. Summary of the Invention

[0013] The object of this invention is achieved with a capsule for beverage preparation, comprising a cup-shaped body and a closed membrane attached to the body, the body and the membrane defining a sealed compartment, the capsule walls being adapted to be pierced by a water injection member of a beverage preparation machine for injecting water into the compartment under pressure, and the closed membrane being adapted to pierce an opening member of the machine for dispensing a beverage prepared in the compartment when the water pressure in the compartment reaches a predetermined value, wherein at least the capsule body is made of rigid or semi-rigid molded cellulose pulp, characterized in that it further comprises a multilayer polymer liner attached to the inner surface of the cellulose pulp, the liner comprising: (i) An outermost polymer layer comprising a biodegradable polymer selected from the following list: polybutylene succinate (PBSA), polybutylene adipate (PBAT), starch, cellulose derivatives, polylactic acid (PLA), polyhydroxyalkanoate (PHA), or a combination thereof, the outermost layer having a thickness between 10 and 100 µm, and the outermost layer having an elongation at break between 10% and 800%, and having a melt flow rate (MFR) between 2 and 4 when measured over a period of 10 minutes at 150°C and 2.16 kg pressure, and having a melting point temperature below 80°C. (ii) A first connecting layer (8) comprising a biodegradable modified or functionalized biopolyester obtained from a base biopolyester molecule, such as maleic anhydride, to which a functional group is grafted to provide adhesive functionality and compatibility with two adjacent layers, and having a melting point temperature between 180°C and 230°C and a thickness between 1 and 12 µm. (iii) A barrier layer (9) comprising a polymer selected from one of the following lists: butene glycol-vinyl alcohol copolymer (BVOH), polyvinyl alcohol (PVOH), or a combination thereof, and having a melting point temperature between 180°C and 230°C and a thickness between 1 and 15 µm. (iv) A second connecting layer (10) comprising a biodegradable modified or functionalized polyolefin having a melting point temperature between 180°C and 230°C and a thickness between 1 and 10 µm. (v) An innermost polymer layer (11) comprising a biodegradable polymer selected from the following list: polybutylene succinate (PBSA / bioPBS), polybutylene adipate (PBAT), starch, cellulose derivatives, polylactic acid (PLA), polyhydroxyalkanoate (PHA), or a combination thereof, the innermost layer having a thickness between 10 and 100 µm, and the innermost layer having an elongation at break between 10% and 1000%, the innermost layer having a melt flow rate (MFR) between 4 and 10 when measured over a period of 10 minutes at 190°C and 2.16 kg pressure, and the innermost layer having a melting point temperature between 110°C and 180°C.

[0014] Interestingly, the polymers suitable for this invention are biodegradable polymers, preferably compostable polymers. Home compostability is now well-defined at the national level and primarily based on the international standard EN 13432; therefore, it does not need to be further defined in this specification. Materials or products conforming to these standards can be identified by markings indicating their home compostability. Some examples of national-level home compostability certification include, but are not limited to, the following: TÜV AUSTRIA BELGIUM provides this home compostability certification scheme, and DIN CERTCO provides home compostability certification according to Australian standard AS 5810. Italy has a national standard for composting at ambient temperature, UNI 11183:2006. In November 2015, the French standard "NF T 51-800 Plastics - Specifications for Plastics Suitable for Home Composting" was introduced. This standard is covered in the DIN CERTCO scheme.

[0015] According to the principles of the present invention, a multi-layered liner having a barrier (for oxygen and / or moisture) is provided as an intermediate layer. Careful selection of the physical characteristics of the innermost and outermost layers is crucial. - The outermost layer in contact with the pulp has a low melting point temperature (below 80°C), which provides high cohesion to the pulp. This is because during the thermoforming process from the liner to the pulp body, as the temperature increases, the polymer composition of the outermost layer flows rapidly and the pulp fibers of the body have low viscosity, impregnating the pulp. Subsequently, after the thermoforming step, as the temperature decreases, the polymer layer of the liner hardens and the polymer is completely interwoven between the pulp fibers, making it impossible to delaminate the liner from the pulp body. Furthermore... - The innermost layer, which comes into contact with the beverage ingredients, has a high melting point (above 110°C). This higher melting point than the outermost layer ensures that during the thermoforming of the liner and pulp, the outermost layer melts very rapidly and remains completely liquid until its melting point (which will be lower than the typical thermoforming temperature), allowing it to flow between the cellulose fibers of the pulp. This also ensures that when cooled after thermoforming, the material composition of the outermost layer is interwoven with and adheres to the cellulose fibers of the pulp. Simultaneously, due to the higher melting point of the innermost layer (which is higher than the typical thermoforming temperature), it does not melt during the thermoforming process steps, allowing for easy self-heating and plug separation when the thermoforming of the liner to pulp is complete and the thermoforming mold is opened.

[0016] In one advantageous embodiment of the invention, the innermost layer is annealed to reduce its elongation at break, thus making it less elastic and easier for the blade to puncture.

[0017] "liner" refers to a single-layer or multi-layer film obtained by extrusion blow molding, extrusion lamination, or casting extrusion.

[0018] Single-layer or multi-layer liner applied to a pulp substrate differs from single-layer or multi-layer liners obtained by coating the pulp substrate. Applying a barrier layer to a molded pulp substrate is challenging due to the rough and uneven surface of the molded pulp. Consequently, a thick preparative surface coating is required to smooth the pulp surface before the barrier layer can be applied. If the surface is not smoothed, there is a risk of uneven application of the barrier layer, resulting in undercoating in some areas and thus weakening the barrier properties of the entire article. The application of a liner does not cause this problem because all layers are pre-formed uniformly, ensuring that the barrier layer is homogeneous across the entire surface of the liner before it is applied to the molded pulp substrate. Therefore, barrier quality across the entire surface of the resulting article is guaranteed, requiring less polymer material than a coating.

[0019] Furthermore, coatings are typically applied to flat sheets of substrate material. However, capsules have a three-dimensional geometry, making it difficult (if not impossible) to coat them with a thin layer of molten polymer.

[0020] In one preferred embodiment of the present invention, the cup-shaped body includes a perimeter to which the closing membrane is attached.

[0021] Advantageously, at least the outermost layer, the innermost layer, the barrier layer, and the connecting layer are co-extruded (extruded and cast) layers.

[0022] In one proposed embodiment, the outermost and / or innermost layers of the multilayer polymer liner are biodegradable polymer-based.

[0023] In one preferred embodiment of the invention, the closing film is made of an extruded coated paper, a fiber spin-coated paper, or a polymer film comprising a compatible polymer material. This ensures optimal sealing adhesion between the liner and the closing film when the capsule is closed.

[0024] Preferably, the ingredient contained in the capsule according to the present invention is roasted and ground coffee. Simple Explanation of the Diagram

[0025] In the following description of the present preferred embodiments with reference to the accompanying drawings, additional features and advantages of the invention are described and will be apparent, in which: [ [Figure 1] []] is a schematic cross-sectional view of the capsule according to the present invention; [ [Figure 2] []] is a schematic cross-sectional view of the multilayer gasket according to the present invention; [ [Figure 3A] []、][ [Figure 3B] []、][ [Figure 4A] []to][ [Figure 4C] []]and[ [Figure 5] []] is a schematic diagram illustrating the different steps of attaching the barrier liner to the pulp cup-shaped body according to the present invention. Implementation

[0026] like [picture] As shown in the embodiment of [1], the present invention relates to a beverage preparation capsule 1, which includes a cup-shaped capsule body 2, the cup-shaped capsule body being covered on its inner surface by oxygen and a barrier liner 3. The capsule body 2 further includes a periphery 4 surrounding an opening, the opening being closed by a membrane 5 sealed on the periphery 4. The capsule body closed by the membrane 5 defines a compartment 6, which is used to contain roasted and ground coffee ingredients.

[0027] The barrier liner 3 is a multilayer membrane, and an embodiment thereof is illustrated in [illustration]. [picture] [2]. In this embodiment, the liner comprises the following layers attached to each other.

[0028] First, it comprises an outermost polymer layer 7, which is formulated based on polybutylene terephthalate adipate (PBAT). This outermost layer has a thickness of 17 µm and an elongation at break of 600%, and acts as an adhesive to the pulp. It is also characterized by a melt flow rate (MFR) (measured over 10 minutes at 150°C and 2.16 kg pressure) and a melting point temperature of 75°C.

[0029] Depending on the application, the thickness of the outermost layer can vary between 10 and 100 µm.

[0030] A first linker layer 8, made of maleic anhydride-grafted biopolyester, is attached to the outermost layer 7. It has a melting point temperature of 200°C and a thickness of 4 µm. The linker layer 8 is an adhesive layer that tightly bonds the outermost layer 7 to the barrier layer 9, which will now be described.

[0031] Located in the middle of the multi-layered liner structure as the core layer, the barrier layer 9 is made of butene glycol-vinyl alcohol copolymer (BVOH) and has a melting point temperature of 200°C and a thickness of 8 µm. This barrier layer provides a barrier to the transfer of oxygen and moisture between the external atmosphere and the capsule compartments.

[0032] A second linker layer 10, made of maleic anhydride-grafted biopolyester, is attached to the barrier layer 9, having a melting point temperature of 200°C and a thickness of 4 µm.

[0033] Finally, in this embodiment, [picture] The gasket illustrated in [2] comprises an innermost polymer layer 11, which is made from a formulation based on polybutylene terephthalate adipate (PBAT). This innermost layer has a thickness of 17 µm and an elongation at break of 177%. It is also characterized by a melt flow rate (MFR) of 6 (measured over a period of 10 minutes at 190°C and 2.16 kg pressure). This layer has a melting point temperature of 115°C.

[0034] Depending on the application, the thickness of the innermost layer can vary between 10 and 100 µm.

[0035] Additionally, depending on requirements, the multilayer polymer liner 3 can have a symmetrical or asymmetrical structure, depending on the thickness of the different layers, especially the outermost and innermost layers.

[0036] As a preference, the outermost and / or innermost layers of the multilayer polymer liner are biodegradable polymer-based.

[0037] More precisely, the various layers of the gasket according to the present invention can be selected according to the following table, which provides various thicknesses selectable for each of the different layers: [layer] [Level Name] [Tm () [℃] [)] [MFR] [Total Thickness]

[50]

[60]

[80]

[0100]

[50] [Trade Name of Polymer] [supplier] Outermost layer (adhesive) KF01U 75 3 (150℃ / 10' - 2.16 kg) 17 twenty two 32 42 15 MaterBi NOVAMONT Connection layer BTR800P 200 4 4 4 4 5 MCPP barrier BVE8049P 200 8 8 8 8 10 G polymer MCPP link BTR800P 200 4 4 4 4 5 MCPP Innermost layer (functional) ES03B0* 115 6 (190℃ / 10' - 2.16 kg) 17 twenty two 32 42 15 MaterBi NOVAMONT

[0038] The capsule according to the present invention is manufactured in sequence by the following steps.

[0039] like [picture] As shown in [3A], the capsule cup 12 is first molded from a dry or wet (preferably wet) pulp mixture. Molded cellulose pulp is known in the art and will not be described in more detail in this specification. The pulp cup 12 has an opening 13 into which roasted and ground coffee ingredients can be filled (not shown).

[0040] Next, the barrier liner membrane 3 is provided as a flat sheet 14 and placed above the opening 13 of the pulp cup 12, while the cup 12 is placed in the mold 15, as follows. [picture] [3B] and [picture] [4A] describes this.

[0041] Next, as [picture] As shown in [4B], the plunger 16 is applied to the surface of the flat sheet 14, which moves toward the interior of the cup 12, causing the barrier liner sheet to be pushed toward the interior of the cup until the liner is fully attached to the surface of the pulp cup, as shown. [picture] As shown in [4C]. The technique for attaching the barrier liner sheet 14 to the surface of the pulp cup 12 is mainly based on thermoforming technology.

[0042] Once the attachment process of the barrier liner sheet 14 to the inner surface of the pulp cup 12 is completed, the periphery 4 is trimmed (i.e., cut to the correct diameter) to obtain an empty pulp capsule with barrier properties, such as [picture] As shown in [5], it includes an opening through which coffee powder is filled. The filled capsule is then closed by sealing the membrane 5 to the edge 4 of the capsule.

[0043] It should be understood that various modifications and alterations to the presently preferred embodiments described herein will be readily apparent to those skilled in the art. Such modifications and alterations can be made without departing from the spirit and scope of the invention and without diminishing its accompanying advantages. Therefore, such modifications and alterations do not depart from the specifications of the appended claims.

[0044] 1: Beverage preparation capsules 2: Capsule body 3: Barrier liner / Barrier liner membrane / Multilayer polymer liner 4: Zhouyuan / Yuan 5: Membrane 6: Compartment 7: Outermost polymer layer / outermost layer 8: Connector Layer 9: Barrier layer 10: Connection Layer 11: Innermost polymer layer / innermost layer 12: Capsule Cup / Pulp Cup / Cup 13: Opening 14: Flat sheet / sheet 15: Mold 16: Plunger

Claims

1. A capsule (1) for beverage preparation, comprising a cup-shaped body (2) and a closed membrane (5) attached to the body (2), the body (2) and the membrane (5) defining a closed compartment (6), the capsule being adapted to be pierced by a water injection member of a beverage preparation machine for injecting water into the compartment under pressure, and the membrane (5) being adapted to be pierced by an opening member of the machine for dispensing the beverage prepared in the compartment when the water pressure in the compartment reaches a predetermined value, wherein at least the body is made of rigid or semi-rigid molded cellulose pulp, characterized in that it further comprises a multilayer polymer liner (3) attached to the inner surface of the body (2), the liner comprising: (i) The outermost polymer layer (7) comprises a biodegradable polymer selected from the following list: polybutylene succinate (PBSA / bioPBS), polybutylene adipate (PBAT), starch, cellulose derivatives, polylactic acid (PLA), polyhydroxyalkanoate (PHA), or combinations thereof, the outermost polymer layer having a thickness between 10 and 100 µm, and the outermost polymer layer having an elongation at break between 10% and 800%, a melt flow rate (MFR) between 2 and 4 when measured over a period of 10 minutes at 150°C and 2.16 kg pressure, and the outermost polymer layer having a melting point temperature below 80°C, (ii) a first connecting layer (8) comprising a biodegradable modified or functionalized polyolefin, having a melting point temperature between 180°C and 230°C and a thickness between 1 and 12 µm, (iii) (iv) A barrier layer (9) comprising a polymer selected from the following list: butene glycol vinyl alcohol copolymer (BVOH), polyvinyl alcohol (PVOH), or combinations thereof, and having a melting point temperature between 180°C and 230°C and a thickness between 1 and 15 µm; (v) A second connecting layer (10) comprising a biodegradable modified or functionalized polyolefin, having a melting point temperature between 180°C and 230°C and a thickness between 1 and 10 µm; (v) An innermost polymer layer (11) comprising a biodegradable polymer selected from the following list: polybutylene succinate (PBSA), polybutylene adipate terephthalate (PBAT), starch, cellulose derivatives, polylactic acid (PLA), polyhydroxyalkanoate (PHA), or combinations thereof, the innermost polymer layer having a melting point temperature between 10 and 100 µm and a thickness between 10 and 100 µm. The innermost polymer layer has a thickness between µm and has an elongation between 10% and 1000% upon rupture, a melt flow rate (MFR) between 4 and 10 when measured over a period of 10 minutes at 190°C and 2.16 kg pressure, and a melting point temperature between 110°C and 180°C.

2. The capsule (1) of claim 1, wherein the cup-shaped body (2) includes a periphery (4) to which the closing membrane (5) is attached.

3. The capsule (1) of claim 1 or 2, wherein at least the outermost polymer layer (7), the innermost polymer layer (11), the barrier layer (9) and the connecting layer (8, 10) are co-extruded layers.

4. The capsule (1) of claim 1 or 2, wherein the closure membrane (5) is made of extruded coated paper, fiber spin-coated paper, or a polymer membrane containing a compatible polymer material.

5. The capsule (1) of claim 1 or 2, wherein the polymer of the innermost polymer layer (11) is an annealed polymer.

6. The capsule (1) of claim 1 or 2, wherein the outermost polymer layer (7) and the innermost polymer layer (11) of the multilayer polymer liner (3) have different thicknesses.

7. The capsule (1) of claim 1 or 2, wherein the outermost polymer layer (7) and / or the innermost polymer layer (11) of the multilayer polymer liner (3) is bio-based with a biodegradable polymer system.

8. The capsule (1) of claim 1 or 2, wherein the ingredient is roasted and ground coffee.

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