RU2852508C2 - Beverage preparation capsule containing barrier insert attached to pulp body - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention relates to a recyclable beverage preparation capsule. The capsule (1) comprises a cup-shaped body (2) made of moulded cellulose pulp and a closing membrane (5) attached to said body (2), a multilayer polymer liner (3) attached to the inner surface of the cellulose pulp body (2). The liner comprises: (i) an outer polymer layer (7) having an elongation at break from 10% to 800%, a melt flow rate (MFR) from 2 to 4 and a melting point below 80°C, (ii) a first bonding layer (8), (iii) a barrier layer (9), (iv) a second bonding layer (10), (v) an inner polymer layer (11) comprising a biodegradable polymer. The inner layer has a thickness from 10 to 100 mcm, an elongation at break from 10% to 1000%, a melt flow rate (MFR) from 4 to 10 and a melting point from 110°C to 180°C.

EFFECT: elimination of delamination of the liner from the body when it is pierced for beverage preparation.

8 cl, 5 dwg, 1 tbl

Description

Field of technology to which the invention relates

The present invention relates to a capsule for preparing a beverage, which is suitable for recycling in a paper recycling process and comprises an outer body made of pressed cellulose pulp, which is supplemented by a gas- and moisture-proof insert that fits tightly to the said body made of pulp.

State of the art

Capsules and tablets for preparing beverages in beverage preparation devices are well known. They offer a convenient and clean way to consume beverages. In the following description, the general term "capsule" will be used, encompassing single-use beverage packaging designed to produce beverages for human consumption by inserting them into a beverage preparation device, which is designed to inject liquid—in principle, hot water—into the packaging for mixing with the contained ingredient. Examples of such beverage packaging are not limited to hard capsules, but also include hard, semi-rigid, or flexible tablets, discs, cartridges of various types, and even sachet-type containers.

Typically, these capsules are made from plastics such as polyolefins or biodegradable plastics, which are usually injected or thermoformed to form a cup that is filled with the ingredient and then sealed with a membrane to hermetically seal the capsule from exposure to gas and moisture.

In recent years, there has been growing awareness of the environmental impact of packaging plastics and a need for new packaging solutions that are either biodegradable after use or recyclable, and in particular those where used packaging can be either composted or recycled through a recycling process suitable for paper or cardboard (the "post-consumer recycling process").

Recently, beverage capsules have been developed that are made from cellulose pulp (or "cellulose pulp" or "paper pulp"), which is molded to form a rigid or semi-rigid capsule body in the shape of a cup, which serves as a container for the beverage's starting ingredient, such as roasted and ground coffee. The cup-shaped body is sealed by attaching (e.g., by sealing) a wall, such as a membrane or film, to it.

To ensure the freshness of the beverage's original ingredient throughout the capsule's lifespan, and especially during storage prior to use, it is necessary to incorporate a barrier material into the cellulose pulp (as well as the sealing membrane) that prevents oxygen and moisture penetration. This barrier material essentially takes the form of a so-called "barrier liner," which is a single- or multi-layer film bonded to the inner surface of the pulp body (i.e., the surface facing the ingredient). The liner is attached to the pulp body by thermoforming both components in a mold.

During beverage preparation, the capsule is inserted into the brewing chamber of the beverage preparation device. The device includes a water injection device, such as a set of blades configured to pierce the capsule body and inject water under pressure. The water mixes with the ingredient, resulting in the beverage. When the water pressure increases and reaches a certain level, the sealing membrane deflects outward and presses against the piercing unit of the beverage preparation device. Once the membrane is pierced, the beverage can flow out of the capsule and into the cup.

WO2021/145764 A1 describes a container comprising a molded fibrous matrix and having a biodegradable multilayer material on its inner surface. The biodegradable multilayer material has a five-layer structure, in which the inner cover layer and outer cover layer are composed of biodegradable aliphatic polyester and include a functional barrier layer composed of PVA as a middle layer. First and second intermediate layers made of biodegradable material are provided for joining and/or sealing adjacent layers.

WO2015/082982 A1 proposes a capsule comprising a body made of paper material and a plastic laminate structure made of PLA/PVC/PLA.

WO2020/114995 A2 describes a capsule comprising a body made of cellulose (paper) and a plastic laminate structure made of PLA/PVA/PLA with a specific elongation at break value of between 2% and 20% of the entire laminate structure.

Preparing beverages using cellulose-based capsules, as described above, is a very promising way to reduce the environmental impact of packaging. However, a technical flaw was discovered when the water injection unit's blades pierced the capsule body. When the water injection unit's blades pierce the capsule body made of pulp, the blades capture the pulp, and as they move toward the capsule's interior, the pulp on the blades separates the liner from the body and pushes the liner without puncturing it. This peeling effect is enhanced by the liner's higher elasticity than that of the pulp. As a result, the unpunctured liner moves inside the capsule, and when water injection begins, no water enters the capsule compartment: the capsule is blocked, and no beverage is released.

The purpose of the present invention is to provide a technical solution to the above-mentioned problem of delamination in beverage capsules made from molded pulp and having a barrier liner.

disclosure of invention

The aim of the present invention is a capsule for preparing a beverage, comprising a cup-shaped body and a closing membrane attached to said body, wherein said body and membrane form a closed compartment for an ingredient, wherein said walls of the capsule are designed with the possibility of being pierced by a water injection device in a beverage preparation device for injecting water under pressure into the compartment, and said closing membrane is designed with the possibility of being pierced by an opening means in said device for dispensing a beverage prepared in said compartment, when the water pressure inside the compartment reaches a predetermined value, wherein at least said capsule body is made of a rigid or semi-rigid molded cellulose pulp, wherein the capsule is characterized in that it further comprises a multilayer polymer liner attached to the inner surface of the cellulose pulp, wherein said liner contains:

(i) an outer polymer layer comprising a biodegradable polymer selected from the following list: polybutylene succinate (PBSA), polybutylene adipate terephthalate (PBAT), starch, cellulose derivatives, polylactic acid (PLA), polyhydroxyalkanoates (PHA) or a combination thereof, wherein said outer layer has a thickness of from 10 to 100 μm, and wherein the first outer layer has an elongation at break in the range of from 10% to 800%, a melt flow rate (MFR) in the range of 2 to 4 when measured at 150°C for 10 minutes under a pressure of 2.16 kg and a melting point below 80°C,

(ii) a first connecting layer (8) consisting of a biodegradable modified or functionalized biopolyester obtained from a biopolyester base molecule to which a functional group such as maleic anhydride is grafted to provide adhesion and compatibility with two adjacent layers, and having a melting temperature of from 180°C to 230°C and a thickness of from 1 to 12 μm,

(iii) a barrier layer (9) comprising a polymer selected from the following list: butenediol-vinyl alcohol copolymer (BVOH), polyvinyl alcohol (PVA) or a combination thereof, and having a melting point in the range from 180°C to 230°C and a thickness in the range from 1 to 15 μm,

(iv) a second connecting layer (10) comprising a biodegradable modified or functionalized polyolefin having a melting point in the range of 180°C to 230°C and a thickness in the range of 1 to 10 μm,

(v) an inner polymer layer (11) comprising a biodegradable polymer selected from the following list: polybutylene succinate (PBSA/bio-PBS), polybutylene adipate terephthalate (PBAT), starch, cellulose derivatives, polylactic acid (PLA), polyhydroxyalkanoates (PHA) or a combination thereof, wherein said inner layer has a thickness of 10 to 100 μm, an elongation at break in the range of 10% to 1000%, a melt flow rate (MFR) in the range of 4 to 10 when measured at 190°C for 10 minutes under a pressure of 2.16 kg and a melting point in the range of 110°C to 180°C.

Notably, the polymers suitable for this invention are biodegradable, preferably home-compostable. Home compostability is currently well defined at the national level and relies heavily on the international standard EN 13432, so further details on this matter are not required in this specification. Materials or products that meet these standards can be recognized by a conformity marking indicating home compostability. Some examples of national-level certification for home compostability include, but are not limited to, the following. The certification body TÜV AUSTRIA BELGIUM offers such a home composting certification scheme, and DIN CERTCO offers home composting certification according to the Australian standard AS 5810. Italy has a national standard, UNI 11183:2006, for compostability at ambient temperature. In November 2015, the French standard NF T 51-800 "Plastics. Specifications for plastics suitable for home composting" was introduced. This standard is included in the DIN CERTCO scheme.

According to the principle of the invention, the multilayer liner has a barrier (for oxygen and/or moisture) as a middle layer. The physical characteristics of the outer and inner layers are carefully selected as follows:

- the outer layer in contact with the pulp has a low melting point (below 80°C), which ensures high cohesion with the pulp; this is due to the fact that during the thermoforming of the liner to the pulp body, as the temperature rises, the low-viscosity flow of the polymer constituting the outer layer quickly flows between the fibers of the pulp from which the body is made and impregnates the pulp; then, when the temperature decreases after the thermoforming stage, the polymer layer of the liner hardens, and the polymer completely penetrates between the fibers of the pulp, so that peeling of the liner from the pulp body becomes impossible; and in addition

- the inner layer, which is in contact with the beverage ingredient, has a high melting point (above 110°C). A higher melting point than the outer layer ensures that during thermoforming of the pulp liner, the said outer layer melts very quickly and becomes completely liquid due to its melting point, which is lower than the normal thermoforming temperature, so that it flows between the cellulose fibers of the pulp, and upon cooling after thermoforming, the material constituting the said outer layer comes into contact with the cellulose fibers of the pulp and adheres to them. At the same time, the inner layer does not melt during the thermoforming process due to its higher melting point (which is higher than the normal thermoforming temperature), so it can be easily separated from the thermoforming mandrel when thermoforming of the pulp liner is completed and the thermoforming mold is opened.

In one advantageous embodiment of the invention, the inner layer is annealed to reduce its elongation at break, making it less elastic and making it even easier to pierce with blades.

By "liner" we mean a monolayer or multilayer film produced by blown film extrusion, extrusion lamination, or flat-die extrusion.

A monolayer or multilayer liner bonded to a pulp support differs from a monolayer or multilayer obtained by coating the pulp support. Applying a barrier layer to a molded pulp support is challenging because the surface of molded pulp is rough and uneven. As a result, a thick preparatory surface coating must be applied to smooth the pulp surface before applying the barrier layer. If the surface is uneven, there is a risk that the barrier layer will be applied unevenly, with some areas lacking sufficient coverage, which will reduce the barrier properties of the entire product. Using a liner does not present these challenges, as all layers are preformed uniformly, ensuring a uniform barrier layer across the entire surface of the liner before it is applied to the molded pulp support. Therefore, the entire surface of the resulting product has barrier properties, requiring less polymer material to achieve these properties than a coating.

Furthermore, the coating is typically applied to a flat sheet of substrate material. However, the capsule has a three-dimensional geometric shape, making it difficult to apply a coating from a thin layer of molten polymer.

In a preferred embodiment of the invention, the cup-shaped body comprises a peripheral edge to which a closing membrane is attached.

Preferably, at least the outer, inner, barrier and connecting layers are produced by co-extrusion (extrusion molding).

In the proposed embodiment, the biodegradable polymer of the outer and/or inner layers of the multilayer polymer liner is obtained from biological raw materials.

In a preferred embodiment of the invention, the closure membrane is made of extrusion-coated paper, spun-bonded paper, or a polymer film composed of a compatible polymeric material. This is necessary to ensure optimal adhesion between the liner and the closure membrane when the capsule is closed.

Preferably, the ingredient contained in the capsule according to the present invention is roasted and ground coffee.

Brief description of graphic drawings

Additional features and advantages of the present invention are disclosed in the description and will be apparent from the description of the presently preferred embodiments, which are given below with reference to the following drawings:

Fig. 1 shows a schematic sectional view of a capsule according to the invention;

Fig. 2 shows a schematic sectional view of a multilayer liner in accordance with the invention;

Fig. 3A, 3B, 4A-4C and 5 are schematic illustrations of various steps in attaching a barrier liner to a pulp cup body in accordance with the invention.

Implementation of the invention

As shown in the embodiment in Fig. 1, the invention relates to a capsule 1 for preparing a beverage, comprising a cup-shaped capsule body 2, coated on the inner surface with an oxygen-protective liner 3. The capsule body 2 further comprises a peripheral edge 4, which surrounds an opening, wherein said opening is closed by a membrane 5, which is glued to the edge 4. The capsule body, closed by the membrane 5, forms a compartment 6 for the ingredient contained therein - roasted and ground coffee.

The barrier liner 3 is a multilayer film, an embodiment of which is shown in Fig. 2. In this embodiment, the liner comprises the following layers attached to each other.

First, it contains an outer polymer layer 7, made of a polybutylene adipate terephthalate (PBAT)-based compound. This outer layer has a thickness of 17 µm and an elongation at break of 600% and serves as an adhesive for bonding to the pulp. It also has a melt flow rate (MFR) of 3 (measured at 150°C for 10 minutes under a pressure of 2.16 kg) and a melting point of 75°C.

The thickness of the outer layer can vary from 10 to 100 microns depending on the application conditions.

Attached to the outer layer 7 is a first connecting layer 8 made of maleic anhydride-grafted biopolyester, having a melting point of 200°C and a thickness of 4 μm. Connecting layer 8 is an adhesive layer that firmly bonds the outer layer 7 to the barrier layer 9, which will be described below.

The core layer, located in the center of the multilayer liner structure, is a barrier layer 9 made of butenediol-vinyl alcohol (BVOH) copolymer with a melting point of 200°C and a thickness of 8 µm. This barrier layer prevents the transfer of oxygen and moisture from the external atmosphere into the capsule compartment.

A second connecting layer 10 made of biopolyester grafted with maleic anhydride, having a melting temperature of 200°C and a thickness of 4 μm, is attached to the barrier layer 9.

Finally, the liner in this embodiment, shown in Fig. 2, comprises an inner polymer layer 11 made of a polybutylene adipate terephthalate (PBAT)-based compound. The thickness of this inner layer is 17 μm, and the elongation at break is 177%. It also has a melt flow rate (MFR) of 6, measured at 190°C for 10 minutes under a pressure of 2.16 kg. This layer has a melting point of 115°C.

The thickness of the inner layer can vary in the range from 10 to 100 microns depending on the application conditions.

In addition, according to the needs, the multilayer polymer liner 3 may have a symmetrical or asymmetrical structure depending on the thickness of the various layers, especially the outer and inner layers.

In a preferred embodiment, the biodegradable polymer of the outer and/or inner layers of the multilayer polymer liner is made from biological raw materials.

In particular, the various layers of the liner according to the present invention can be selected from the following table with different thickness values that can be selected for each of the various layers:

Layer Brand name Tm (°C) MFR Total thickness 50 60 80 100 50 Commercial name of the polymer Supplier Outer layer (adhesive) KF01U 75 3 (150°C/
10 minutes - 2.16 kg) 17 22 32 42 15 MaterBi NOVAMONT Connecting layer BTR800P 200 4 4 4 4 5 MCPP Barrier BVE8049P 200 8 8 8 8 10 G-polymer MCPP Connective BTR800P 200 4 4 4 4 5 MCPP Inner layer (functional) ES03B0* 115 6 (190°C/
10 minutes - 2.16 kg) 17 22 32 42 15 MaterBi NOVAMONT

The capsule according to the invention is manufactured in the following order.

As shown in Fig. 3A, the capsule cup 12 is first formed from a dry or wet (preferably wet) pulp mixture. Forming cellulose pulp is already known and will not be discussed in more detail here. The pulp cup 12 has an opening 13 into which an ingredient—roasted and ground coffee (not shown)—can be poured.

A barrier liner film 3 is then provided in the form of a flat sheet 14, which is placed over the opening 13 of the pulp cup 12, said cup 12 being placed in a mould 15, as shown in Fig. 3B and 4A.

Then, as shown in Fig. 4B, the plunger 16 acts on the surface of the flat sheet 14, which is moved toward the inside of the cup 12 in such a way that the sheet of the barrier liner is pressed against the inside of the cup until said liner is completely attached to the surface of the pulp cup, as shown in Fig. 4C. The method for attaching the sheet 14 of the barrier liner to the surface of the pulp cup 12 is based primarily on thermoforming methods.

After attaching the barrier liner sheet 14 to the inner surface of the pulp cup 12, the peripheral edge 4 is trimmed (i.e., cut to the correct diameter) to form an empty pulp capsule with barrier properties, as shown in Fig. 5, which contains an opening through which coffee powder is added. The filled capsule is then closed by sealing the membrane 5 onto the edge 4 of said capsule.

It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention or diminishing its inherent advantages. It is therefore intended that the appended claims cover such changes and modifications.

Claims (13)

1. A capsule (1) for preparing a beverage, comprising a cup-shaped body (2) and a closing membrane (5) attached to said body (2), wherein said body (2) and membrane (5) form a closed compartment (6) for an ingredient, wherein said capsule is configured to be pierced by a water injection device of the beverage preparation device for injecting water under pressure into the compartment, and said membrane (5) is configured to be pierced by an opening means in said device for dispensing a beverage prepared in said compartment when the water pressure inside the compartment reaches a predetermined value, wherein at least said capsule 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) made of cellulose pulp, wherein said liner comprises: (i) an outer polymer layer (7) comprising a biodegradable polymer selected from the following list: polybutylene succinate (PBSA/bio-PBS), polybutylene adipate terephthalate (PBAT), starch, cellulose derivatives, polylactic acid (PLA), polyhydroxyalkanoates (PHA) or a combination thereof, wherein said outer layer has a thickness of from 10 to 100 μm, and wherein said outer layer has an elongation at break in the range of from 10% to 800%, a melt flow rate (MFR) in the range of 2 to 4 when measured at 150°C for 10 minutes under a pressure of 2.16 kg and a melting point below 80°C, (ii) a first connecting layer (8) comprising a biodegradable modified or functionalized polyolefin having a melting point in the range of 180°C to 230°C and a thickness in the range of 1 to 12 μm, (iii) a barrier layer (9) comprising a polymer selected from the following list: butenediol-vinyl alcohol copolymer (BVOH), polyvinyl alcohol (PVA) or a combination thereof, and having a melting point in the range from 180°C to 230°C and a thickness in the range from 1 to 15 μm, (iv) a second connecting layer (10) comprising a biodegradable modified or functionalized polyolefin having a melting point in the range of 180°C to 230°C and a thickness in the range of 1 to 10 μm, (v) an inner 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), polyhydroxyalkanoates (PHA) or a combination thereof, wherein said inner layer has a thickness of 10 to 100 μm, an elongation at break in the range of 10% to 1000%, a melt flow rate (MFR) in the range of 4 to 10 when measured at 190°C for 10 minutes under a pressure of 2.16 kg and a melting point in the range of 110°C to 180°C. 2. A capsule (1) according to claim 1, in which said cup-shaped body (2) comprises a peripheral edge (4) to which a closing membrane (5) is attached. 3. A capsule (1) according to any one of claims 1 or 2, in which at least the outer (7), inner (11), barrier (9) and connecting layers (8, 10) are coextruded layers. 4. A capsule (1) according to any of the preceding claims, wherein the closing membrane (5) is made of extrusion-coated paper, spun-bonded paper or a polymeric film consisting of a compatible polymeric material. 5. A capsule (1) according to any one of the preceding claims, wherein the polymer of the inner layer (11) is an annealed polymer. 6. A capsule (1) according to any of the preceding claims, in which the outer layer (7) and the inner layer (11) of the multilayer polymer liner (3) have different thicknesses. 7. A capsule (1) according to any of the preceding claims, in which the biodegradable polymer of the outer (7) and/or inner (11) layers of the multilayer polymer insert (3) is made from biological raw materials. 8. A capsule (1) according to any one of the preceding claims, wherein said ingredient is roasted and ground coffee.