Patent Application
20230114944
The present invention relates to a container for ingredients for making beverages in the form of a truncated cone. The present invention furthermore relates to a process for preparing this container, a capsule for making beverages, the use thereof for making beverages, and a process for making beverages.
The present invention most specifically relates to a capsule for holding ingredients of a hot aqueous beverage, such as coffee, tea or the like.
Often, coffee powder or tea powder is contained in capsules which are inserted in a beverage system which is typically a coffee or tea extraction device.
Devices of this type are generally known. US 2005/0183578 A1 discloses a system for dispensing short and long coffee beverages from cartridges containing ground coffee in which water is injected under pressure, and the prepared coffee is collected in a receiving device. The cartridges comprise an airtight container portion with a retaining member sealed around the edges of the container portion. The retaining member can be a membrane. This membrane of the cartridge is not opened until a certain opening pressure is built within the cartridge by virtue of water coming in the cartridge. The internal pressure building up inside the cartridge makes the retaining member to deform and press on an engaging means up to a point where it becomes pierced or torn open. The cartridge starts opening at a certain opening pressure. After the opening, the extraction takes place at a high extraction pressure level.
WO 2014/067507 discloses a capsule for receiving a brewing product like coffee, tea and the like, and a method for sealing the same capsule. The capsule is defined by three parts, namely capsule head, capsule wall and capsule foot. The capsule foot is the designated outlet side of the brewed beverage, e.g. the coffee beverage, the tea beverage, the milk beverage or a soup beverage. The capsule is typically designed to be essentially frustroconical or otherwise tapered from the capsule foot to the capsule head. The capsule is made of polybutylene terephthalate due to the unexpectedly high aroma-tight suitability for the purposes of the capsule.
WO 2019/068597 discloses a container made of polybutylene terephthalate having a low oxygen-permeability. The container can be made of polybutylene terephthalate, an oxidizable polyester-ether and a salt of a transition metal. The material is described as having a sufficient durability combined with sufficient oxygen barrier as well as sufficient water vapor barrier.
US 2016/0122530 A1 discloses compositions containing polybutylene terephthalate and also mentions coffee capsules.
Coffee capsules are widely used for making single portions of coffee or other beverages. The capsules often have a volume of 10 to 20 ml and a weight of more than 1 g. A minimum wall thickness is required to withstand the buckling pressure when hot water flows through the capsule under pressure.
In order to reduce the significant amount of waste material, it would be advantageous to provide lighter capsules or containers which maintain the same buckling pressure level as current capsules. Furthermore, it is desirable that the capsules comprise stacking elements that ease the filling of the capsules and improve the stackability of the (empty) capsules and the separation of capsules from the stack for filling.
Therefore, the object underlying the present invention is to provide a container for ingredients for making beverages which maintains the buckling pressures of known capsules but has a reduced weight. The capsule or container should be sufficiently mechanically stable so that it can be used in the common coffee makers.
The object is achieved by a container for ingredients for making beverages in the form of a rotation-symmetric truncated cone which is open at the larger bottom end of the truncated cone and closed at the smaller top end of the truncated cone by a top section of the truncated cone which preferably is of a flat, rounded, inclined or dented form or a combination of these forms, wherein the larger bottom end of the truncated cone can be closed by a base plate or membrane and can have an outward flange section to which the base plate or membrane can be attached, and wherein the thickness of the container wall is non-uniform, the container wall forming one or more circumferential stiffening rings which cover 10 to 50% of the container height, and wherein the wall thickness of the stiffening rings is at least 50% higher than the wall thickness in the remaining container wall outside the stiffening rings, the container having a maximum height of 5 cm and a maximum diameter without flange of 6 cm.
The object is furthermore achieved by a process for preparing this containing by injection-molding the material forming the container.
The object is furthermore achieved by a capsule for making beverages, containing ingredients for making beverages, preferably coffee powder, tea powder, tea leaves, milk, milk powder, cocoa powder, or soft drink components, in a container, as defined above, which is closed at the bottom end by a base plate or membrane.
The capsule therefore comprises the container, base plate or membrane, and ingredients.
The object is furthermore achieved by the use of this capsule for making beverages.
The object is furthermore achieved by a process for making beverages by inserting the capsule, as defined above, in a beverage-preparing apparatus in which water inlet and outlet holes are provided in the capsule, preferably by puncturing the top section and the base plate or membrane thereof, and a water stream is directed through the capsule and recovered in a beverage recipient.
According to the present invention it was found that the weight of containers for ingredients for making beverages can be reduced without impairing the mechanical properties, if the thickness of the container wall is non-uniform and the container wall forms one or more circumferential stiffening rings. The one or more stiffening rings cover 10 to 50% of the container height.
By providing these stiffening rings, it is possible to reduce the remaining container thickness so that a net weight reduction of the container can be achieved without impairing the mechanical properties.
The container according to the present invention has the form of a rotation-symmetric truncated cone as the principle shape. The term “rotation-symmetric” defines that the truncated cone can be turned around the symmetry axis at an angle of 90°, 180° and 270° without changing the shape. It is possible to provide indentations or dents in the truncated cone in a regular pattern so that the rotation around the symmetry axis after 90°, 180° and 270° results in a shape that is identical with the starting shape. Preferably, the term “rotation-symmetric” defines two or more symmetry planes in which the symmetry axis is contained. More preferably, there are at least 2 to 20 symmetry planes running through the symmetry axis.
Therefore, the term “rotation-symmetric” is fulfilled for truncated cones which have a regular pattern of indentations or dents around the circumference of the container. An exemplary BISIO capsule design shows a number of outward bulges or dents of the container which are arranged in a regular pattern near the top of the container.
The container is open at the larger bottom end of the truncated cone so that it can receive the ingredients for making beverages. This larger bottom end of the truncated cone will be closed after filling in the ingredients for making beverages by a base plate or membrane.
In order to ease the closing of the bottom opening, an outward flange section can be provided at the bottom of the container. This outward flange is preferably perpendicular to the rotational symmetry axis of the container so that a flat flange section or clamp flange is obtained to which a flat base plate or membrane can be attached in a suitable manner. For example, the base plate or membrane can be attached or mounted to the larger bottom end of the truncated cone by glueing, welding or hot-pressing, depending on the material of the base plate or membrane.
The container is closed at the smaller top end of the truncated cone. This smaller top end of the truncated cone can also be described as the gate location or tapping zone. This top section of the truncated cone can be of any desired shape that allows for the tapping of the container upon use in a beverage-making apparatus. Any desired shape of the top section that achieves the required tapping can be employed according to the present invention. Preferably, the top section of the truncated cone is of a flat, rounded, inclined or dented form, or a combination of these forms. Typical designs include an outwardly contorted top section which at its center is inwardly contorted for receiving the tapping device in its center. For example, the top section may be outwardly rounded with an inclined, inwardly rounded or flat top which receives the tapping device.
Typically, the truncated cone including the top section is prepared in one piece, for example by injection-molding of the container material.
The base plate or membrane, however, is typically separately formed and attached or mounted to the open bottom end of the container only after filling in the ingredients for making beverages. It would be possible also to form the base plate together with the container in one piece.
The thickness of the container wall, specifically of the truncated cone part of the container wall, is non-uniform. The container wall contains or forms one or more circumferential stiffening rings or zones which have an increased thickness with regard to the other sections of the truncated cone outside the stiffening rings or zones.
The term “circumferential stiffening ring” defines the container wall’s ring-shaped stiffening zone which has the rotational symmetry axis of the truncated cone as its center. The stiffening ring runs around the container at a defined height thereof. Thereby, the truncated cone remains rotation-symmetric since the stiffening rings are formed in a layer perpendicular to the rotational symmetry axis.
The one or more circumferential stiffening rings cover 10 to 50% of the container height, preferably 15 to 40% of the container height, more preferably 20 to 35% of the container height. The container height is measured along the rotational symmetry axis.
Furthermore, preferably 10 to 50% of the truncated cone area are covered by the stiffening rings, more preferably 15 to 40% of the truncated cone area, most preferably 20 to 35% of the truncated cone area.
The wall thickness of the container in the stiffening ring zones is at least 50% higher in the container wall than outside the stiffening rings. For example, when the truncated cone has a wall thickness of 0.2 mm outside the stiffening ring, the wall thickness of or within the stiffening rings is at least 0.3 mm.
Preferably, the wall thickness of or in the stiffening rings is at least 2 times the thickness outside the stiffening rings. In a preferred embodiment, the wall thickness in the stiffening rings is 1.5 to 4 times, more preferably 1.5 to 2.5 times the thickness outside the stiffening rings.
The stiffening rings can be formed in the outer and/or inner wall of the container. Thereby, it is possible to achieve an even outside wall of the truncated cone or even inside wall of the truncated cone. Furthermore, it is possible that the one or more stiffening rings have the form of a step when a cross-section of the container is viewed. In this embodiment it is possible that the truncated cone shows a step-wise widening at the location of the stiffening ring.
The wall thickness can have a smooth or continuous transition from normal wall thickness to stiffening ring wall thickness. On the other hand, it is also possible to have a step-wise increase from normal wall thickness to stiffening ring wall thickness.
Preferably, the stiffening rings are located in a section extending from 10% to 90%, preferably 20% to 80% of the container height. Thereby, the top 10% and the bottom 10% of the container height, more preferably the top 20% and the bottom 20% of the container height, do not contain stiffening rings.
The stiffening rings or stiffening zones are preferably formed from the same material as the remaining container wall. In this sense, the expression “stiffening ring” means a container wall having an increased wall thickness compared to the wall thickness outside the stiffening rings. For example, the container wall can have two different thicknesses: the higher thickness within the stiffening ring or stiffening ring zone, and the lower thickness in the remaining part of the container wall.
The stiffening rigs can also act as stacking elements, which facilitate the stacking of the containers and their separation from the stacks. Optionally, additional stacking elements can be provided in the container walls.
The container has one or more circumferential stiffening rings. Preferably, 1 to 5 stiffening rings, more preferably 1 to 4 stiffening rings, more preferably 1 to 3 stiffening rings are provided in the container wall. Most preferred containers according to the present invention have one, two or three stiffening rings formed in the container wall.
According to a preferred embodiment of the invention, the container has 3 stiffening rings, one of the stiffening rings being located in the middle third of the container height, one additional stiffening ring being located above this middle stiffening ring, and one additional stiffening ring located below this middle stiffening ring.
Preferably, one of the stiffening rings is located in the middle third of the container height, and therefore in the central portion of the container. More preferably, one of the stiffening rings is located in the middle 20% of the container height.
The container according to the present invention has a maximum height of 5 cm, more preferably of 4 cm, most preferably of 3 cm. The minimum height is preferably 1.5 cm, more preferably 2 cm, most preferably 2.5 cm. Preferably, the container height (measured along the rotational symmetry axis) is from 1.5 to 5 cm, more preferably 2 to 4 cm, most preferably 2.5 to 3 cm.
The maximum (outer) diameter of the container, located at the bottom thereof, without flange, is at most 6 cm, preferably most 4 cm, more preferably at most 3 cm. The maximum diameter, without flange, preferably is at least 1.5 cm, more preferably at least 2 cm, most preferably at least 2.2 cm. Preferably, the maximum diameter of the container is in the range of from 1.5 to 6 cm, more preferably 2 to 4 cm, most preferably 2.2 to 3 cm.
The height of the container is measured along the rotational symmetry axis, whereas the (outer) diameter is measured perpendicular to the rotational symmetry axis. Diameters are outer diameters, if not indicated otherwise.
The inner volume of the container is preferably in the range of from 5 to 50 ml, more preferably 7.5 to 25 ml, most preferably 10 to 20 ml.
According to one embodiment of the invention, the height of the container is in the range of from 2 to 3.5 cm and/or the cone diameter of the top section of the truncated cone is in the range of from 1.6 to 2.8 cm and/or the cone diameter at the bottom of the truncated cone, without flange, is in the range of from 1.8 to 3.2 cm. Preferred is a combination of the above height and diameters.
A preferred container has a height of the container in the range of from 2.4 to 3 cm, a cone diameter of the top section of the truncated cone in the range of from 1.9 to 2.5 cm, and a cone diameter at the bottom of the truncated cone, without flange, in the range of from 2.2 to 2.8 cm.
The maximum diameter, with flange, is preferably 0.2 to 2 cm, more preferably 0.4 to 1.5 cm, most preferably 0.7 to 1.2 cm larger than the maximum diameter, without flange.
One exemplary container according to the present invention has a height 2.7 cm, a cone diameter of the top section of the truncated cone of 2.2 cm, a cone diameter at the bottom of the truncated cone, without flange, of 2.5 cm, and a cone diameter at the bottom of the truncated cone, with flange, of 3.4 cm.
The container wall thickness can be chosen depending on the desired buckling pressure, burst pressure or critical buckling load. Preferably, the container wall thickness is in the range of from 0.1 to 1.0 mm, more preferably 0.2 to 0.8 mm, most preferably 0.2 to 0.6 mm. For example, the wall thickness in the zone of the stiffening rings can be 0.4 mm, and outside the stiffening rings 0.2 mm. In a preferred embodiment, the wall thickness in the zone of the stiffening rings is in the range of from 0.3 to 0.6 mm, more preferably 0.3 to 0.5 mm, whereas the wall thickness outside the stiffening rings is from 0.15 to 0.25 mm, more preferably 0.2 to 0.25 mm.
If more than one stiffening ring is provided in the container, the stiffening rings can have the same or different diameters. In a preferred embodiment, in which one stiffening ring is located in the middle third of the container height, and one additional stiffening ring is located above this middle stiffening ring, and one additional stiffening ring is located below this middle stiffening ring, the wall thickness of the middle stiffening ring can be higher than the wall thickness of the upper and lower stiffening rings.
By employing the stiffening rings in the truncated cone surface, an overall decrease of container weight can be achieved. Even when the stiffening rings cover 50% of the container height or truncated cone area, a weight reduction can be achieved, since the thickness reduction in the areas outside the stiffening rings can be higher than the wall thickness increase in the area of the stiffening rings.
The material of the container can be freely chosen from materials that do not have a safety hazard when in contact with food. For example, the container can be formed of a metal, like aluminium. Preferably, however, the container is formed of a thermoplastic polymer. The thermoplastic polymer can be widely chosen from all thermoplastic polymers that do not pose a safety hazard when in contact with food. Preferred thermoplastic polymers are polyolefins, polystyrene, polyalkylene terephthalates, polyesters. Most preferred are polyethylene, polypropylene, polystyrene, polybutylene terephthalate and biodegradable polyesters, like polybutylene succinate (PBS) or biodegradable polyesters which can be obtained from BASF SE under the trademark ecoflex®.
The number average molecular weight as well as the weight average molecular weight (Mn, Mw) and polydispersity data which follow can be obtained using gel permeation chromatography (GPC) in hexafluoroisopropanol as solvent with PMMA calibration.
This molecular weight determination can be employed for all components of the thermoplastic molding compositions according to the present invention.
Preferred thermoplastic polymers are polyesters which are e.g. described in WO 2017/063841 and WO 2019/068597.
Polyesters (A) that can be employed are typically based on an aromatic dicarboxylic acid and on an aliphatic or aromatic dihydroxy compound.
Polyalkylene terephthalates, in particular those having from 2 to 10 carbon atoms in the alcohol moiety, are a first group of preferred polyesters.
These polyalkylene terephthalates are known per se and are described in the literature. They comprise, in the main chain, an aromatic ring that derives from the aromatic dicarboxylic acid. The aromatic ring can also have substitution, e.g. by halogen, such as chlorine and bromine, or by C1-C4-alkyl groups, such as methyl, ethyl, isopropyl, n-propyl, and n-butyl, isobutyl and tert-butyl groups.
These polyalkylene terephthalates can be produced by reaction of aromatic dicarboxylic acids, or their esters or other ester-forming derivatives, with aliphatic dihydroxy compounds in a manner known per se.
Preferred dicarboxylic acids that may be mentioned are 2,6-naphthalenedicarboxylic acid, terephthalic acid and isophthalic acid and mixtures thereof. Up to 30 mol%, preferably not more than 10 mol%, of the aromatic dicarboxylic acids can be replaced by aliphatic or cycloaliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acids and cyclohexanedicarboxylic acids.
Among the aliphatic dihydroxy compounds, preference is given to diols having from 2 to 6 carbon atoms, in particular 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and neopentyl glycol and mixtures of these.
Particularly preferred polyesters (A) that may be mentioned are polyalkylene terephthalates that derive from alkanediols having from 2 to 6 carbon atoms. Among these, preference is in particular given to polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate and mixtures of these. Preference is further given to PET and/or PBT which comprise up to 1 wt%, preferably up to 0.75 wt%, of 1,6-hexanediol and/or 2-methyl-1,5-pentanediol as further monomer units.
The number average molar mass (Mn) of the polyesters (A) is generally in the range from 5000 to 100 000 g/mol, in particular in the range from 10 000 to 75 000 g/mol, preferably in the range from 15 000 to 38 000 g/mol, while their weight average molar mass (Mw) is from 30 000 to 300 000 g/mol, preferably from 60 000 to 200 000 g/mol, and their Mw/Mn ratio is from 1 to 6, preferably from 2 to 4.
The intrinsic viscosity of the polyesters (A) is generally in the range from 50 to 220, preferably from 80 to 160 (measured in 0.5% by weight solution in a phenol/o-dichlorobenzene mixture (ration by weight 1:1 at 25° C.) in accordance with ISO 1628).
Preference is in particular given to polyesters having carboxy end group content of up to 100 meq/kg of polyester, preferably up to 50 meq/kg, and in particular up to 40 meq/kg. These polyesters can by way of example be produced by the process of DE-A 44 01 055. Carboxy end group content is usually determined by titration methods (e.g. potentiometry).
It is moreover advantageous to use PET recyclates (also known as scrap PET), optionally in a mixture with polyalkylene terephthalates such as PBT.
The term recyclates generally means:
Both types of recyclate may be used either as regrind or in the form of pellets. In the latter case, the crude recycled materials are isolated and purified and then melted and pelletized using an extruder. This usually facilitates handling and free-flowing properties, and metering for further steps in processing.
The recycled materials used may either be pelletized or in the form of regrind. The edge length should not be more than 10 mm and should preferably be less than 8 mm.
Because polyesters undergo hydrolytic cleavage during processing (due to traces of moisture) it is advisable to pre-dry the recycled material. Residual moisture content after drying is preferably < 0.2%, in particular < 0.05%.
Another group to be mentioned is that of fully aromatic polyesters deriving from aromatic dicarboxylic acids and aromatic dihydroxy compounds.
Suitable aromatic dicarboxylic acids are the compounds previously described for the polyalkylene terephthalates. Preference is given to use of mixtures of from 5 to 100 mol% of isophthalic acid and from 0 to 95 mol% of terephthalic acid, in particular to mixtures of about 80% to 50% of terephthalic acid with from 20% to 50% of isophthalic acid.
The aromatic dihydroxy compounds preferably have the general formula
in which Z is an alkylene or cycloalkylene group having up to 8 carbon atoms, an arylene group having up to 12 carbon atoms, a carbonyl group, a sulfonyl group, an oxygen atom or sulfur atom, or a chemical bond, and in which m has the value from 0 to 2. The phenylene groups in the compounds may also have substitution by C1-C6-alkyl groups or alkoxy groups, and fluorine, chlorine, or bromine.
Examples of parent compounds for these compounds are
Among these, preference is given to
It is, of course, also possible to use mixtures of polyalkylene terephthalates and fully aromatic polyesters. These generally comprise from 20 to 98 wt% of the polyalkylene terephthalate and from 2 to 80 wt% of the fully aromatic polyester.
It is, of course, also possible to use polyester block copolymers, such as copolyetheresters. Products of this type are known per se and are described in the literature, e.g. in US 3,651,014. Corresponding products are also available commercially, e.g. Hytrel® (DuPont).
Halogen free polycarbonates are also polyesters in the invention. Examples of suitable halogen-free polycarbonates are those based on biphenols of the general formula
in which Q is a single bond, a C1-C8-alkylene group, a C2-C3-alkylidene group, a C3-C6-cycloalkylidene group, a C6-C12-arylene group, or else —O—, —S— or —SO2—, and m is an integer from 0 to 2.
The phenylene radicals of the biphenols may also have substituents, such as C1-C6-alkyl or C1-C6-alkoxy.
Examples of preferred biphenols of the formula are hydroquinone, resorcinol, 4,4′-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane and 1,1-bis(4-hydroxyphenyl)cyclohexane. Particular preference is given to 2,2-bis(4-hydroxyphenyl)propane and 1,1-bis(4-hydroxyphenyl)cyclohexane, and also to 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.
Either homopolycarbonates or copolycarbonates are suitable as component A, and preference is given to the copolycarbonates of bisphenol A, as well as to bisphenol A homopolymer.
Suitable polycarbonates may be branched in a known manner, specifically and preferably by incorporating from 0.05 to 2.0 mol%, based on the total of the biphenols used, of at least trifunctional compounds, for example those having three or more phenolic OH groups.
Polycarbonates which have proven particularly suitable have relative viscosities ηrel of from 1.10 to 1.50, in particular from 1.25 to 1.40. This corresponds to average molar masses Mw (weight average) of from 10 000 to 200 000 g/mol, preferably from 20 000 to 80 000 g/mol.
The biphenols of the general formula are known per se or can be produced by known processes.
The polycarbonates may, for example, be produced by reacting the biphenols with phosgene in the interfacial process, or with phosgene in the homogeneous-phase process (known as the pyridine process), and in each case the desired molecular weight is achieved in a known manner by using an appropriate amount of known chain terminators. (In relation to polydiorganosiloxane-containing polycarbonates see, for example, DE 33 34 782 A1.)
Examples of suitable chain terminators are phenol, p-tert-butylphenol, or else long-chain alkylphenols, such as 4-(1,3-tetramethylbutyl)phenol, as in DE 28 42 005 A1, or monoalkylphenols, or dialkylphenols with a total of from 8 to 20 carbon atoms in the alkyl substituents, as in DE 35 06 472 A1, such as p-nonylphenyl, 3,5-di-tert-butylphenol, p-tert-octylphenol, p-dodecylphenol, 2-(3,5-dimethylheptyl)phenol and 4-(3,5-dimethylheptyl)phenol.
For the purposes of the present invention, the expression halogen-free polycarbonates means polycarbonates made from halogen-free biphenols, from halogen-free chain terminators and optionally from halogen-free branching agents, where the content of subordinate amounts at the ppm level of hydrolysable chlorine, resulting, for example, from the production of the polycarbonates with phosgene in the interfacial process, is not regarded as meriting the term halogen-containing for the purposes of the invention. Polycarbonates of this type with contents of hydrolysable chlorine at the ppm level are halogen-free polycarbonates for the purposes of the present invention.
Other suitable components (A) that may be mentioned are amorphous polyester carbonates, where phosgene has been replaced during a production process by aromatic dicarboxylic acid units such as isophthalic acid and/or terephthalic acid units. Reference may be made at this point to EP 0 711 810 A1 for further details.
Other suitable copolycarbonates having cycloalkyl moieties as monomer units are described in EP 0 365 916 A1.
Bisphenol A can moreover be replaced by bisphenol TMC. Polycarbonates of this type are obtainable commercially from Bayer with trademark APEC HT®.
Suitable polyesters (B) of the poly e-caprolactone type exhibit the following structure:
They are usually produced by ring-opening polymerization of e-caprolactone.
These polymers are semicrystalline, and are classified as biodegradable polyesters.
According to the online encyclopedia ROMPP Lexikon Chemie (www.roempp.thieme.de), these are polymers which are degraded in the presence of microorganisms in a biologically active environment (compost, etc.). (In contrast to oxo-degradable polyesters and UV-initiated polyester degradation.)
The average molar mass Mw of preferred components (B) is from 5000 to 200 000 g/mol, in particular from 50 000 to 140 000 g/mol (determined by means of GPC with hexafluoroisopropanol and 0.05% of potassium trifluoroacetate as solvent, using PMMA as standard).
Melting range (DSC, 20 K/min in accordance with DIN 11357) is generally from 80 to 150, preferably from 100 to 130° C.
Products of this type are obtainable commercially by way of example from Perstorp as Capa®.
Biodegradable polyesters (C) can also be used, which are preferably aliphatic-aromatic polyesters or semiaromatic polyesters. They show a biodegradation behavior similar or equal to that of PBAT, PBSeT, PBS and PLA mentioned below.
The expression “aliphatic-aromatic polyesters (C)” means linear, chain-extended, and preferably branched and chain-extended, polyesters, as described by way of example in WO 96/15173 to 15176 or in WO 98/12242. Mixtures of various semiaromatic polyesters can equally be used.
More recent developments that are of interest are based on renewable raw materials (see WO 2010/034689). In particular, the expression “polyesters (C)” means products such as ecoflex® (BASF SE).
Among the preferred polyesters (C) are polyesters comprising as significant components:
Aliphatic diacids and the corresponding derivatives C1) that can be used are those having from 6 to 20 carbon atoms, preferably from 6 to 10 carbon atoms. They can be either linear or branched. In principle, however, it is also possible to use dicarboxylic acids having a larger number of carbon atoms, for example having up to 30 carbon atoms.
The following may be mentioned by way of example: 2-methylglutaric acid, 3-methylglutaric acid, α-ketoglutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, brassylic acid, suberic acid, and itaconic acid. It is possible here to use the dicarboxylic acids or ester-forming derivatives of these, individually or as mixture of two or more thereof.
It is preferable to use adipic acid, azelaic acid, sebacic acid, brassylic acid or respective ester-forming derivatives thereof or a mixture thereof. It is particularly preferably to use adipic acid or sebacic acid or respective ester-forming derivatives thereof or mixtures thereof.
Preference is in particular given to the following aliphatic-aromatic polyesters: polybutylene adipate terephthalate (PBAT), polybutylene sebacate terephthalate (PBSeT), polylactic acid (PLA), polybutylene succinate (PBS), and mixtures of two or more thereof, and blends containing one or more of these polyesters.
The aromatic dicarboxylic acids or ester-forming derivatives thereof C2) can be used individually or in the form of mixture of two or more thereof. Particular preference is given to use of terephthalic acid or ester-forming derivatives thereof, for example dimethyl terephthalate.
The diols C3) - 1,4-butanediol and 1,3-propanediol - are obtainable in the form of renewable raw material. It is also possible to use mixtures of the diols mentioned.
Use is generally made of from 0.05 to 1.5 wt%, preferably from 0.1 to 1.0 wt%, and with particular preference from 0.1 to 0.3 wt%, based on the total weight of the polyester, of a branching agent, and/or of from 0.05 to 1 wt%, preferably from 0.1 to 1.0 wt%, based on the total weight of the polyester, of a chain extender C4), selected from the group consisting of: a polyfunctional isocyanate, isocyanurate, oxazoline, carboxylic anhydride such as maleic anhydride, epoxide (in particular an epoxide-containing poly(meth)acrylate), an at least trihydric alcohol or an at least tribasic carboxylic acid. Compounds that can be used as chain extenders C4) are polyfunctional and in particular difunctional isocyanates, isocyanurates, oxazolines or epoxides.
Other compounds that can be regarded as branching agents are chain extenders, and also alcohols or carboxylic acid derivatives, having at least three functional groups. Particularly preferred compounds have from three to six functional groups. The following may be mentioned by way of example: tartaric acid, citric acid, malic acid, trimesic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid and pyromellitic dianhydride; trimethylolpropane, trimethylolethane; pentaerythritol, polyethertriols and glycerol. Preference is given to polyols such as trimethylolpropane, pentaerythritol and in particular glycerol. By means of components C4) it is possible to construct biodegradable polyesters that have pseudoplastic properties. The rheology of the melts improves; easier processing of the biodegradable polyesters becomes possible.
It is generally advisable to add the branching (at least trifunctional) compounds at a relatively early juncture in the polymerization procedure.
Examples of suitable bifunctional chain extenders are tolylene 2,4-diisocyanate, tolylene 2,6-diisocyanate, diphenylmethane 2,2′-diisocyanate, diphenylmethane 2,4′-diisocyanate, diphenylmethane 4,4′-diisocyanate, naphthylene 1,5-diisocyanate, xylylene diisocyanate, hexamethylene 1,6-diisocyanate, isophorone diisocyanate and methylene bis(4-isocyanatocyclohexane). Particular preference is given to isophorone diisocyanate and in particular to hexamethylene 1,6-diisocyanate.
The number average molar mass (Mn) of the polyesters (C) is generally in the range from 5000 to 100 000 g/mol, in particular in the range from 10 000 to 75 000 g/mol, preferably in the range from 15 000 to 38 000 g/mol, while their weight average molar mass (Mw) is from 30 000 to 300 000 g/mol, preferably from 60 000 to 200 000 g/mol, and their Mw/Mn ratio is from 1 to 6, preferably from 2 to 4. Intrinsic viscosity is preferably from 50 to 450, preferably from 80 to 250 g/ml (measured in o-dichlorobenzene/phenol (ratio by weight 50/50). Melting point is in the range from 85 to 150° C., preferably in the range from 95 to 140° C.
MVR (melt volume rate) in accordance with EN ISO 1133-1 DE (190° C., 2.16 kg weight) is generally from 0.5 to 8 cm3/10 min, preferably from 0.8 to 6 cm3/10 min. Acid numbers in accordance with DIN EN 12634 are generally from 0.01 to 1.2 mg KOH/g, preferably from 0.01 to 1.0 mg KOH/g and with particular preference from 0.01 to 0.7 mg KOH/g.
The polybutylene terephthalate (PBT) and the other polyester can be produced in a manner known per se via reaction of aromatic dicarboxylic acids, aliphatic dicarboxylic acids or cycloaliphatic dicarboxylic acids, or their esters or ester-forming derivatives, with 1,4-butanediol.
Examples of aliphatic or cycloaliphatic dicarboxylic acids are adipic acid, azelaic acid, sebacic acid, dodecane dicarboxylic acid and cyclohexane dicarboxylic acid.
Polybutylene terephthalate may contain small amounts of aromatic dicarboxylic acids which differ from terephthalic acid. Examples thereof are 2,6-naphthalene dicarboxylic acid or isophthalic acid which can replace up to 20 mol%, preferably up to 10 mol%, specifically up to 5 mol% of the terephthalic acid units. Most preferably, only terephthalic acid units are present in the polybutylene terephthalate.
Furthermore, it is possible, that minor amounts of 1,4-butanediol can be replaced by 1,6-hexanediol and/or 2-methyl-1,5-pentanediol as other monomer units. The amount thereof should be less than 1 wt%, preferably less than 0.75 wt% of the diol units.
The intrinsic viscosity of the polybutylene terephthalate is generally in the range from 50 to 220, preferably from 80 to 160 (measured in 0.5% by weight solution in a phenol-o-dichlorobenzene mixture (ratio by weight: 1:1 at 25° C.) in accordance with ISO 1628).
When the container according to the present invention is injection-molded, the PBT preferably has a viscosity number in the range of from 70 to 130 cm3/g, more preferably in the range of from 75 to 115 cm3/g, specifically in the range of from 80 to 100 cm3/g.
The viscosity number is usually determined according to ISO 1628.
The terminal carboxyl group content of the polybutylene terephthalate is preferably up to 100 meq/kg PBT, preferably up to 50 meq/kg PBT, and in particular up to 40 meq/kg PBT. Polyethers of this type can be for example produced by the process as described in DE 44 01 055 A1. Terminal carboxyl group content is usually determined by titration methods (e.g. potentiometry).
Particularly preferred polybutylene terephthalate are produced with Ti catalysts. Residual Ti content of these after the polymerization process is preferably less than 250 ppm, more preferably less than 200 ppm, most preferably less than 150 ppm.
The polybutylene terephthalate can be combined with 0.1 to 10 wt% of an oxidizable polyester-ether and 5 to 10000 wt-ppm of a salt of a transition metal. This preferred combination is described below.
The term “oxidizable polyester-ether” means that in the presence of an oxidation catalyst, oxygen coming from the surrounding air can be able to oxidize the polyester-ether. In this way, the oxygen coming from the surrounding air is scavenged, so that the polyester-ether functions as an oxygen scavenger.
Suitable polyester-ethers are generally known and described for example in WO 2012/126951.
The polyester-ether preferably comprises at least one polyether segment comprising poly(tetramethylene-co-alkylene ether), in which the alkylene group can be C2 to C4, for example poly(tetramethylene-co-ethylene ether). The molecular weight of the polyether segment can vary from approximately 200 g/mol to approximately 5000 g/mol, for example from approximately 1000 g/mol to approximately 3000 g/mol. The molar percentage of alkylene oxide in the polyether segment can be approximately 10 mol% to approximately 90 mol%, for example approximately 25 mol% to approximately 75 mol% or approximately 40 mol% to approximately 60 mol%. For use in preparation of the copolyester ether, the terminal group of the polyether segment is hydroxyl, for example it is a poly(tetramethylene-co-alkylene oxide) glycol which can be for example poly(tetramethylene-co-ethylene oxide) glycol or poly(tetramethylene-co-propylene oxide) glycol. The tetramethylene ether group can be derived from tetrahydrofuran.
Other poly(alkylene oxide) glycols can be used in combination with the poly(tetramethylene-co-alkylene oxide) glycols described above, for example poly(ethylene oxide) glycol, poly(trimethylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(pentamethylene oxide) glycol, poly(hexamethylene oxide) glycol, poly(heptamethylene oxide) glycol, poly(octamethylene oxide) glycol or poly(alkylene oxide) glycols derived from monomers of cyclic ethers, for example derived from 2,3-didrofuran.
The copolyester ethers can contain the polyether segment in the interval from approximately 15 wt% to 95 wt% of the copolyester ether, for example approximately 25 wt% to approximately 75 wt% or approximately 30 wt% to approximately 70 wt% of the copolyester ether, using ethylene glycol, butanediol or propanediol as another glycol. The dicarboxylic acid can be terephthalic acid or dimethyl terephthalate. Antioxidants and photoinitiators can be added in polymerization to control initiation of the oxygen scavenging. Copolyesters-ethers as defined above are marketed for example by Eastman Chemical Company under the name ECDEL® 9967.
The total quantity of the copolyester ether in the final composition is chosen to guarantee the desired oxygen scavenging properties of the article formed by the composition. The quantities of copolyester ether can vary from 0.1 to 10 wt% of the total composition, preferably from 0.5 to 5.0 wt%, more preferably from 0.7 to 3.0 wt% of the total composition. The copolyester ether can be physically mixed with the polyester. Alternatively the poly(tetramethylene-co-alkylene oxide) glycol and the other poly(alkylene oxide) glycol can be copolymerized with the polyester.
The salt of the transition metal is an oxidation catalyst which activates and/or promotes oxidation of the copolyester-ether, so as to produce an active barrier to the passage of oxygen by means of oxygen scavenging.
The transition metal is in the form of salt and is chosen from the first, second or third series of the Periodic Table. Suitable transition metals are cobalt, copper, rhodium, ruthenium, palladium, tungsten, osmium, cadmium, silver, tantalum, hafnium, vanadium, titanium, chromium, nickel, zinc, manganese or their mixtures. Suitable counter-ions for the metal include, without limitation, carboxylates, such as neodecanoates, octanoates, stearates, acetates, naphthalates, lactates, maleates, acetylacetonates, linoleates, oleates, palmitates or 2-ethyl hexanoates, oxides, borates, carbonates, chlorides, dioxides, hydroxides, nitrates, phosphates, sulphates, silicates or their mixtures. For example, cobalt stearate and cobalt acetate are oxidation catalysts which can be used in the present invention.
The oxidation catalyst can be added during the polymerization or by preparation of a master-batch with the oxidizable polymer or with the PBT included in the molding composition. The latter mode of adding the catalyst is preferred.
The amount of transition metal salt as oxidation catalyst ranges from 5 to 10000 weight-ppm, preferably from 100 to 5000 weight-ppm, more preferably from 200 to 2000 weight-ppm.
According to one embodiment of the invention, the thermoplastic molding composition is free from zinc compounds and especially the polybutylene terephthalate is not prepared by employing a zinc compound selected from the group consisting of zinc oxide, zinc hydroxide, zinc alkoxide, aliphatic acid salt of zinc, zinc acetate, zinc oxalate, zinc citrate, zinc carbonate, zinc halide and a complex compound of zinc; for example zinc acetate. Specifically the compositions do not contain any zinc acetate according to one embodiment of the invention.
The molding compositions can furthermore comprise additives chosen from the thermal and UV stabilizers, anti-blocking agents, antioxidants, antistatic agents, fillers and others known to persons skilled in the art. The additives can be added in the polymerization processes or in the subsequent transformation phases.
Oxidation retarders and heat stabilizers, UV stabilizers, colorants, plasticizers and fluorine-containing ethylene polymers are described in US 2016/0122530 in paragraphs [0151] to [0164].
Also dispersing aids like talcum can be used. The amount of talcum is preferably in the range of from 0.02 to 1 wt%, more preferably 0.05 to 0.5 wt%, most preferably 0.07 to 0.2 wt%.
Further ingredients for the molding composition of which the container is formed can be found in WO 2019/068597.
A polyester molding composition with low emission of total organic carbons which can be employed as the molding composition is described in US 2016/122530 A1.
Suitable polyolefins are polyethylene and polypropylene which preferably have a number average molecular weight of from 1000 to 100000 g/mol, more preferably of from 5000 to 40000 g/mol, most preferably of around 20000 g/mol. For a further description of the polyolefins, reference can be made to Borealis BJ356MO.
The containers described above are preferably prepared by injection-molding the material forming the container.
Also multilayer compositions of polymers can be employed, as described in WO 2012/126951.
The container according to the present invention is used for containing ingredients for making beverages. Thus, the container is used for packaging ingredients for making beverages. These ingredients can be e.g. coffee powder, tea powder, tea leaves, herbs, milk, milk powder, cocoa powder or soft drink components. Also other ingredients, like dried food pieces used for making fruit tea, can be considered.
The container will be closed after filling so that it is sealed. In order to achieve this, the container is closed by a base plate or membrane, as described above. This base plate or membrane can be made of a film of a thermoplastic molding composition. This base plate, membrane or film can be heat-sealable on said container, or it can be glued to the container. The material for the base plate or membrane or film can be freely chosen. For example, it can be made of aluminium foil, or a thermoplastic polymer.
Most preferably, the base plate or membrane or film is made from the thermoplastic molding composition which is also used for making the container. This leads to a better recyclability of the whole container after use, since only one single material is employed. The base plate or membrane can be connected with the container via a ligament or fixed link, and thus be produced in one piece. After filling, the base plate or membrane can be folded onto the container and adhered thereto.
Most preferably, the container is a capsule, for example a coffee capsule, which is widely used in coffee machines in which a single dosage unit of coffee is inserted in capsule form in the coffee machine. Typical sizes of these capsules which are employed in e.g. coffee machines are known to the person skilled in the art.
The capsule for making beverages contains ingredients for making beverages in a container as defined above which is closed at the bottom end by a base plate or membrane.
The total weight of the filled capsule is preferably in the range of from 1 to 5 g, more preferably 1.2 to 2.5 g, most preferably 1.2 to 2.8 g.
The capsule is used for making beverages by directing a water stream through the capsule.
The process for making beverages includes inserting a capsule in a beverage-preparing apparatus, providing water inlet and outlet holes in the capsule, e.g. by puncturing the top section and the base plate or membrane thereof, and directing a water stream through the capsule, and recovering the beverage in a beverage recipient.
These processes are e.g. described in WO 2014/067507 and US 2005/0183578 A1.
The capsules according to the present invention combine a weight reduction with maintained or improved buckling pressure, thereby maintaining the collapse resistance.
The invention is further illustrated by the following examples.
The capsule showed a buckling pressure of 0.66 bar and a weight of 1.6 g.
A comparative capsule having a constant 0.7 mm wall thickness has a buckling pressure of 1.1 bar and a weight of 2.64 g.
The buckling pressure of this capsule is 0.40 bar and the capsule has a weight of 1.49 g.
If, for comparison, a constant wall thickness of 0.3 mm was employed, the buckling pressure was 0.3 bar.
Two comparative coffee capsules which can be found in the marketplace were compared with a capsule design according to the present invention, where three stiffening rings were provided in the truncated cone. The stiffening rings cover approximately 22% of the capsule height.
The results are shown in enclosed
However, for the capsule containing three stiffening rings according to the present invention, the buckling pressure could be increased to 0.497 bar which is significantly higher when compared to the buckling pressure of the comparative designs.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20164890.4 | Mar 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/057346 | 3/23/2021 | WO |
