CONTAINER CLOSURE WITH A SEALING ELEMENT

Abstract

The invention relates to a container closure (1, 21, 41, 61) with a sealing element (3, 23, 43, 63). The sealing element (3, 23, 43, 63) comprises a polymer composition. The polymer composition comprises a butene copolymer. The butene copolymer has a melting temperature T.sub.m of between 30° C. and 130° C., wherein the melting temperature T. is determined by the second heating curve of a DSC measurement at a heating rate of 10° C. min.sup.−1

Claims

1. A closure (1, 21, 41, 61) having a sealing element (3, 23, 43, 63), wherein (a) the sealing element (3, 23, 43, 63) comprises a polymer composition; and (b) the polymer composition comprises a butene copolymer, wherein the butene copolymer has a melting temperature T.sub.m between 30° C. and 130° C., wherein the melting temperature T.sub.m is determined by the second heating curve of a DSC-measurement at a heating rate of 10° C.

2. The closure according to claim 1, wherein the melting temperature T.sub.m of the butene copolymer lies between 40° C. and 125° C., particularly between 80° C. and 125° C.

3. The closure according to claim 1, wherein propylene is a comonomer of the butene copolymer.

4. The closure according to claim 1, wherein the butene copolymer is a bipolymer.

5. The closure according to claim 1, wherein the butene copolymer is contained in the polymer composition at a ratio between 0.1 wt.-% and 80 wt.-%, preferably between 5 wt.-% and 60 wt.-%, particularly preferred between 8 wt.-% and 55 wt.-%.

6. The closure according to claim1, wherein the polymer composition comprises a further butene copolymer, wherein the further butene copolymer is a different kind of polymer.

7. The closure according to claim 6, wherein one comonomer of the further butene copolymer is ethylene.

8. The closure according to claim 6, wherein the further butene copolymer is a butene bipolymer.

9. The closure according to claim 6, wherein the further butene copolymer is in the polymer composition at a ratio between 10 wt.-% and 80 wt.-%.

10. The closure according to claim 1, wherein the polymer composition further comprises a polyethylene.

11. The closure according to claim 10, wherein the polyethylene is a homo-polyethylene.

12. The closure according to claim 10, wherein the polyethylene is in the polymer composition at a ratio between 5 wt.-% and 60 wt.-%.

13. The closure according to claim 1, wherein the polymer composition further comprises a random propylene copolymer.

14. The closure according to claim 13, wherein ethylene is a comonomer of the random propylene copolymer.

15. The closure according to claim 13, wherein the random propylene copolymer is a bipolymer.

16. The closure according to claim 13, wherein the random propylene copolymer is in the polymer composition at a ratio between 5 wt.-% and 60 wt. %.

17. The closure according to claim 1, wherein the polymer composition further comprises a butene homopolymer.

18. The closure according to claim 17, wherein the butene homopolymer is in the polymer composition at a ratio between 5 wt.-% and 60 wt. %.

19. The closure according to claim 1, wherein the butene copolymer comprises styrene as a comonomer.

20. The closure according to claim 19, wherein the copolymer is SBS, SEPS, SEEPS or SEBS.

21. The closure according to claim 19, wherein the copolymer comprising styrene is in the polymer composition at a ratio between 10 wt.-% and 70 wt. %

22. The closure according to claim 19, wherein the polymer composition further comprises a butene homopolymer.

23. The closure according to claim 22, wherein the butene homopolymer is in the polymer composition at a ratio between 5 wt.-% and 60 wt. %.

24. The closure according to claim 1, wherein the butene copolymer is in the polymer composition at a ratio of at least 80 wt.-%

25. The closure according to claim 1, wherein the polymer composition further comprises from 0 to a maximum of 10 wt.-% homo-polypropylene.

26. The closure according to claim 1, wherein the polymer composition further comprises from 0 to a maximum of 10 wt. %, of a component that is liquid at 20° C. and 1000 hPa.

27. The closure according to claim 1, wherein the polymer composition is a polyolefin composition.

28. The closure according to claim 1, wherein the polymer composition has a static friction coefficient, determined according to DIN EN ISO 8295, of a maximum of 0.50.

29. The closure according to claim 1, wherein the polymer composition comprises one ore more additives at a ratio of up to 15 wt.

30. The closure according to claim 29, wherein the one or more additives are selected from the group consisting of: pigments, nucleating agents, brighteners, stabilizers, tensides, lubricants, antioxidants and combinations thereof.

31. The closure according to claim 1, wherein the closure further comprises a support (11, 31, 51 ,71) and, wherein the support (11, 31, 51,71) comprises metal and/or plastic.

32. The closure according to claim 1, wherein the closure (1, 21, 41, 61) is a screw closure.

33. The closure according to claim 1, wherein the polymer composition has an oxygen permeability rate, determined according to DIN 53380, of less than 500 cm.sup.3 m.sup.−2 d.sup.−1 bar.sup.−1.

34. The closure according to claim 1, wherein the polymer composition has a total migration, determined according to DIN-EN 1186-14, of a maximum of 1.20 mg cm.sup.−2.

35. The closure according to claim 1, wherein the sealing element (3, 23, 43, 63) consists of the polymer composition.

36. A container (5, 25, 45) with a container mouth (5a, 25a, 45a) and a sealable opening at the end of the container mouth, wherein the opening is sealed with a closure (1, 21, 41, 61) according to claim 1.

37. The container according to claim 36, wherein the container is a glass container, a plastic container or a metal container.

38. The container according to claim 36, wherein the closure comprises a support (11, 31, 51, 71) and the sealing element (3, 23, 43, 63), and wherein the sealing element between an upper end (4, 24, 44) of the container mouth and a lower side of the support (11, 31, 51, 71) has a height (h.sub.3) of a maximum of 1.0 mm.

39. The container according to claim 36, wherein the closure comprises a support (11, 31, 51, 71) and the sealing element (3, 23, 43, 63), and wherein the sealing element between an upper end (4, 24, 44) of the container mouth and a lower side of the support (11, 31, 51, 71) has a height (h.sub.3) of at least 0.2 mm in an axial direction of the container.

40. The container according to claim 36, wherein an absolute pressure within the sealed container is not higher than 200 hPa.

41. The container according to claim 36, wherein the container has a safety dimension of a maximum of 10 mm.

42.-57. (canceled)

Description

[0082] The embodiments of the invention are shown on the basis of an example and not in a way that allows limitations from the figures to be transferred or read into the claims. Like reference numerals in the figures stand for like elements.

[0083] FIG. 1 shows a side view of a cam screw closure 1 with an annular sealing element 3, partially as a section;

[0084] FIG. 2 shows a side view of the cam screw closure 1 with the sealing element 3 on a container 5, partially as a section;

[0085] FIG. 3 shows the cam screw closure 1 with the sealing element 3 in a view from below;

[0086] FIG. 4 shows an isometric view of a composite closure 61 (combi-twist);

[0087] FIG. 5 partially shows an axial section of the composite closure 61 (combi-twist) of FIG. 4;

[0088] FIG. 6 shows a side view of a press-on twist-off closure 21 (PT-closure) with a sealing element 23, partially as a section;

[0089] FIG. 7 shows a side view of the PT-closure 21 with the sealing element 23 on a container 25, partially as a section;

[0090] FIG. 8 shows a top view of the PT-closure 21;

[0091] FIG. 9 shows a side view of a composite closure 41 (Band-Guard) with a sealing element 43, partially as a section;

[0092] FIG. 10 shows a side view of the composite closure 41 (Band-Guard) with the sealing element 43 at a container 45, partially as a section;

[0093] FIG. 11 shows a top view of the composite closure 41 (Band-Guard);

[0094] FIG. 12 shows an enlarged detail of the cam screw closure of FIG. 2.

[0095] FIGS. 1 and 3 show a cam screw closure 1. The cam screw closure 1 comprises a metallic support 11 and a sealing element 3. In the illustration of FIG. 2, the cam screw closure 1 is applied to a container 5. At the lower end of the cam screw closure 1, a curled portion 9 is formed. Circumferentially distributed, several cams 7 are formed out of the curled portion. The cams 7 are formed by an axial deformation of the curled portion 9 and radially extend farther towards the center of the cam screw closure 1 than the curled portion 9. The cam screw closure 1 shown in FIGS. 1 to 3 comprises four cams 7 that are configured such that they are circumferentially evenly distributed. The sections that are partially shown in FIGS. 1 and 2 correspond to section III-III in FIG. 3.

[0096] Close to the radially outer end section of the cam screw closure 1, a channel 2 is configured in the upper portion 10 of the support 11. The sealing element 3 is at least partially arranged within the channel 2. In this embodiment, the sealing element 3 has an annular shape, in other embodiments, the sealing element 3 may be disc-shaped, especially if the diameter of the cam screw closure is small (e.g. not more than 30 mm).

[0097] For adhesion between the metallic support 11 and the sealing element 3, an adhesive varnish is typically applied to the side of the metallic support 11 that is in contact with the sealing element 3.

[0098] In FIG. 2, the cam screw closure 1 is applied to a container 5. The container 5 comprises a container mouth 5a as an upper portion of the container 5. The container mouth comprises a thread 6 and an upper end 4 of the container mouth 5a. The thread 6 is configured as a circumferential thread in the area of the container mouth 5a and extends circumferentially upwards or downwards (depending on the angle of view).

[0099] In order to apply a cam screw closure 1 onto a container 5, cams 7 are brought into contact with sections of the thread 6 and the cam screw closure 1 is rotated clockwise relative to the container 5. Due to the structural design of the thread 6 and the interaction of the cams 7 with the thread 6, the upper end 4 of the container mouth 5a moves towards the sealing element 3 during the rotary movement of the cam screw closure 1 relative to the container 5. Through a further rotary movement of the cam screw closure 1, the upper end 4 of the container mouth 5a is impressed into the sealing element 3, thus deforming it, so that a portion of the upper end 4 of the container mouth 5a is covered by the sealing element 3, whereby the container 5 is closed tightly. A tight sealing of the container 5 is in particular necessary in order to withstand an increased pressure during a thermal treatment of the sealed container 5 at temperatures above 70° C., 90° C. or even above 120° C.

[0100] The cam screw closure 1, as shown in FIGS. 1 to 3, comprises a safety button 10b that is formed in the upper portion 10 of the support 11. Due to the incline 10a at the upper portion 10 of the support 11, the safety button 10b will tilt towards the middle of the container, if there is a sufficiently high negative pressure within the container. Such a vacuum can be produced by introducing water vapor into the container before sealing the container with the closure.

[0101] When a consumer opens the container by removing the closure, the pressure within the container increases to ambient pressure and the safety button 10b tilts away from the middle of the container. The tilting process of the safety button 10b is accompanied by a characteristic sound indicating to the consumer that there was a vacuum in the container before the latter was opened.

[0102] FIGS. 4 and 5 show a composite closure 61 (combi-twist) that can be applied to a container analogously to the described cam screw closure 1 by means of a rotary movement and that can be removed from the container by a rotary movement.

[0103] The composite closure 61 comprises a support with an upper metallic portion 71 and a plastic portion 72 in L-shape. Close to the radial end of the metallic portion 71 of the support, a channel 78 is formed and a curled portion 77 is configured at the radial end of the metallic portion 71. A sealing element is arranged at least partially within the channel 78.

[0104] Several thread elements 74a, 74b, formed on the inner side of the plastic portion 72, are in contact with a counter thread in the area of the mouth of a container (not shown) onto which the composite closure 61 is to be applied. The plastic portion 72 of the composite closure 61 further comprises a tamper evidence 73 that is configured similar to the tamper evidence shown in FIGS. 9 to 11 and that will be described in more detail with regard to FIGS. 9 to 11.

[0105] When the composite closure 61 is screwed onto a container by means of a rotary movement, this results in an interaction of the container mouth of the container with the sealing element of the composite closure 61 analogous to that described with reference to the cam screw closure 1.

[0106] In FIGS. 6 to 8, a press-on twist-off closure 21 (PT-closure) is shown. The PT-closure 21 comprises a metallic support 31 with a curled portion 29 at the lower end of the support 31 and a safety button 30a in the upper portion 30 of the support 31.

[0107] A sealing element 23 is formed both in the area of the upper portion 30 of the support 31 and, to a considerable extent, at the skirt of the support extending downwards from the upper portion 30 of the support 31. In contrast to the cam screw closure 1 and the composite closure 61, the PT-closure 21 is pressed onto the container mouth 25a when it is being applied to a container 25. While it is being pressed onto the container mouth 25a, the sealing element 23 is sufficiently soft to elastically enclose thread elements 26 of the container mouth 25a. For this purpose, the sealing element 23 is typically treated with water vapor before the PT-closure 21 is applied onto a container 5, so as to achieve the necessary softness of the sealing element 23. When the sealing element 23 has cooled down, a counter thread in the form of a negative of the thread elements 26 of the container mouth has been formed in the sealing element 23.

[0108] An upper end 24 of the container mouth 25a contacts the sealing element 23.

[0109] For opening the container 25, the PT-closure 21 is removed from the container 25 by means of a rotary movement.

[0110] FIGS. 9 to 11 show a composite closure 41 (Band-Guard) that is capable of operating analogously to the described PT-closure 21.

[0111] The composite closure 41 comprises a support with a metallic portion 51 and a plastic portion 52, a tamper evidence 53 and a safety button 50a. The tamper evidence 53 is configured in such a way that it is removed from the rest of the composite closure 41, when the composite closure 41 is removed from a container 45, and serves to give a customer the possibility to check whether the composite closure 41 had already been removed from the container 45 before. The safety button 50a is configured and capable of operating analogously to the safety button 10b of the cam screw closure 1.

[0112] The plastic portion of the composite closure 41 may comprise several axially extending recesses 56 in order to increase the stability of the closure.

[0113] A sealing element 43 is arranged in the composite closure 41 in such a way that it contacts both the metallic portion 51 as well as the plastic portion 52. For sealing a container 45, the composite closure 41 in pressed onto the container mouth 45a of the container 45, so that at least the upper end 44 of the container mouth 45a contacts the sealing element 43.

[0114] The plastic portion 52 of the support comprises several offset protrusions 54 that interact with thread elements 46 of the container mouth 45a. For opening a container 45 that is sealed with the composite closure 41, the composite closure 41 may be rotated relative to the container 45.

[0115] The distance h.sub.3 of a sealing element 3 between an upper end 4 of a container mouth 5a of a container 5 and the lower side of a support 11 of the closure 1 is shown in FIG. 12 with view to a cam screw closure 1 and is described here. The distance (height) h.sub.3 for other closure-types is to be determined analogously.

[0116] The sealing element 3 clamped between the container mouth 5 and the support 11 of the closure 1 has a height h.sub.3 that is given, when a container 5 is sealed with the closure 1. If the height h.sub.3 is too small, there is the risk that the sealing element 3 may be cut through, whereby the tightness of the sealed container 5 might be affected. If the height h.sub.3 is too big, the tightness of the sealed container is affected, since the contact area between the upper end 4 of the container mouth 5a and the sealing element 3 is not large enough. In order to achieve a suitable impression of the upper end 4 of the container mouth 5a into the sealing element, the composition of the sealing element 3 is of decisive importance.

EXAMPLES

[0117] Examples of polymer compositions for sealing elements in a closure are shown in tables 1 and 2.

TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Component Butene propylene copolymer, wt.-% 94.9 47.5 12.0 12.0 Butene ethylene copolymer, wt.-% 47.4 59.9 59.9 LDPE, wt.-% 23.0 HDPE, wt.-% 23.0 Random propylene ethylene- copolymer, wt.-% Homo-polybutene, wt.-% Additives, wt.-% 5.1 5.1 5.1 5.1 Characteristics Friction coefficient, dimensionless 0.32 0.26 0.23 0.17 Total migration, mg cm.sup.−2 0.56 0.79 0.88 0.83 Oxygen permeability rate, 370 364 409 307 cm.sup.3 m.sup.−2 d.sup.−1 bar.sup.−1

TABLE-US-00002 TABLE 2 Example 5 Example 6 Example 7 Component Butene propylene copolymer, wt.-% 12.0 12.0 12.0 Butene ethylene copolymer, wt.-% 59.9 59.9 59.9 LDPE, wt.-% 7.0 HDPE, wt.-% Random propylene ethylene 23.0 16.0 copolymer, wt.-% Homo-polybutene, wt.-% 23.0 Additives, wt.-% 5.1 5.1 5.1 Characteristics Friction coefficient, dimensionless 0.19 0.20 0.17 Total migration, mg cm.sup.−2 1.05 0.81 0.96 Oxygen permeability rate, 413 325 368 cm.sup.3 m.sup.−2 d.sup.−1 bar.sup.−1

[0118] The butene propylene copolymer has a melting temperature of 114° C., determined according to ISO 11357-3.

[0119] A typical value of the oxygen permeability rate of PVC-containing compositions that are utilized as sealing elements in closures lies at approximately 220 cm.sup.3 m.sup.−2 d.sup.−1 bar.sup.−1.

[0120] The oxygen permeability rates of known, commercially available PVC-free compositions in closures typically amount to 650 cm.sup.3 m.sup.−2 d.sup.−1 bar.sup.−1 and more. Often oxygen scavengers are added to these known compositions in order to reduce the presence of oxygen in a container that is sealed with such a closure.

[0121] The PVC-free polymer compositions disclosed herein show oxygen permeability rates that are close to the rates of PVC-containing compositions. The oxygen permeability rates of the compositions disclosed herein lie clearly below the oxygen permeability rates of known PVC-free compositions.

[0122] By means of a polymer composition having a low oxygen permeability rate, the use of oxygen scavenger materials in the polymer composition can be avoided and at the same time a low ingress of oxygen into the filled container will be guaranteed.

[0123] The butene propylene copolymer is available e.g. from LyondellBasell.

[0124] The butene ethylene copolymer used is available e.g. from LyondellBasell. The copolymerized share of butene may amount to at least 80 mol.-%.

[0125] LDPE and HDPE are commercially available from various providers.

[0126] The random propylene ethylene copolymer is available from Borealis.

[0127] Homo-polybutene is available from LyondellBasell.

[0128] SEBS is available from Kraton, for example from the Kraton G-series.