Container closure with a sealing element

Abstract

A vessel closure (1, 21, 41, 61) includes a sealing element (3, 23, 43, 63). The sealing element (3, 23, 43, 63) includes a polymer composition. The polymer composition includes a polysiphaolefin with kinematic viscosity, determined according to ASTM D445/ISO 3104, of at least 4 cSt, at a temperature of 100 C., and/or a dropping point, determined according to ASTM 5950, of at most 10 C., and up to 95% by weight of a second polyolefin.

Claims

1. Vessel closure with a sealing element, whereby the sealing element comprises a polymer composition and the polymer composition comprises (a) a polyalphaolefin with a kinematic viscosity, determined according to ASTM D445/ISO 3104, of at least 4 cSt, at a temperature of 100 C., and a dropping point, determined according to ASTM 5950, of at most 10 C.; and (b) up to 95% by weight of a second polyolefin, wherein the polymer composition is free of a copolymer with styrene as a comonomer.

2. Vessel closure according to claim 1, whereby the polyalphaolefin has a kinematic viscosity at a temperature of 100 C., determined according to ASTM D445/ISO 3104, between 4 cSt and 1500 cSt.

3. Vessel closure according to claim 1, whereby the polyalphaolefin has a dropping point, determined according to ASTM 5950, of at most 20 C.

4. Vessel closure according to claim 1, whereby the polyalphaolefin has a density, determined according to ASTM D4052, of up to 0.860 g per cm.sup.3.

5. Vessel closure according to claim 1, whereby the polyalphaolefin has an average molecular weight Mw, determined according to DIN 55672-1, of at least 440 Da.

6. Vessel closure according to claim 1, whereby the polyalphaolefin has been prepared using a metallocene catalyst.

7. Vessel closure according to claim 1 whereby the polyalphaolefin is present in the polymer composition at a level of up to 65% by weight.

8. Vessel closure according to claim 1, whereby the second polyolefin has a Shore A hardness, determined according to DIN ISO 7619-1 at 23 C., of at most 90.

9. Vessel closure according to claim 1, whereby the second polyolefin is a plastomer or an elastomer with a density, determined according to DIN EN ISO 1183-1, of less than 0.860 g per cm.sup.3.

10. Vessel closure according to claim 1, whereby the second polyolefin is a (random) copolymer comprising alpha-butene and a C.sub.2, C.sub.3 or C.sub.5 to C.sub.16 (alpha-)olefin as comonomers.

11. Vessel closure according to claim 1, whereby the second polyolefin is a (random) copolymer comprising propene and a C.sub.2, C.sub.4 or C.sub.5 to C.sub.16 (alpha-)olefin as comonomers.

12. Vessel closure according to claim 1, whereby the second polyolefin is a (random or block) copolymer comprising ethene and a C.sub.5 to C.sub.16 (alpha-)olefin as comonomers.

13. Vessel closure according to claim 1, whereby the second polyolefin is present in the polymer composition in a proportion of at most 80% by weight.

14. Vessel closure according to claim 1, whereby the polyalphaolefin is a homopolymer or a copolymer wherein the polyalphaolefin comprises a C.sub.3 to C.sub.22 alpha-olefin as a (co)monomer.

15. Vessel closure according to claim 14, whereby the polyalphaolefin includes a C.sub.6 to C.sub.14 alpha-olefin.

16. Vessel closure with a sealing element, whereby the sealing element comprises a polymer composition and the polymer composition comprises (a) a polyalphaolefin with a kinematic viscosity, determined according to ASTM D445/ISO 3104, of at least 4 cSt, at a temperature of 100 C., and a dropping point, determined according to ASTM 5950, of at most 10 C.; and (b) between 65% and 95% by weight of a second polyolefin, wherein the second polyolefin is a copolymer comprising alpha-butene and a C.sub.2, C.sub.3 or C.sub.5 to C.sub.16 (alpha-)olefin as comonomers.

17. Vessel closure with a sealing element, whereby the sealing element comprises a polymer composition and the polymer composition comprises (a) a polyalphaolefin with a kinematic viscosity, determined according to ASTM D445/ISO 3104, of at least 4 cSt, at a temperature of 100 C., and a dropping point, determined according to ASTM 5950, of at most 10 C.; and (b) up to 95% by weight of a second polyolefin, wherein the second polyolefin is a copolymer comprising propene, a C.sub.2 olefin and a C.sub.4 (alpha-)olefin as comonomers.

Description

(1) The embodiments of the invention are illustrated by way of example and not in a manner whereby limitations arising from the figures are transferred or read into the patent claims. Identical reference signs in the figures indicate identical elements.

(2) FIG. 1 shows a side view of a cam screw closure 1 with an annular sealing element 3, in part as a sectional view;

(3) FIG. 2 shows a side view of cam screw rotary closure 1 with sealing element 3 on a vessel 5, in part as a sectional view;

(4) FIG. 3 shows cam screw closure 1 with sealing element 3 in a bottom view;

(5) FIG. 4 shows an isometric view of a composite closure 61 (Combi-Twist);

(6) FIG. 5 shows a partial axial section of the composite closure 61 (Combi-Twist) of FIG. 4;

(7) FIG. 6 shows a side view of a press-on twist-off closure 21 (PT closure) with a sealing element 23, in part as a sectional view;

(8) FIG. 7 shows a side view of PT closure 21 with sealing element 23 on a vessel 25, in part as a sectional view;

(9) FIG. 8 shows a top view of PT closure 21;

(10) FIG. 9 shows a side view of a composite fastener 41 (band guard) with a sealing element 43, in part as a sectional view;

(11) FIG. 10 shows a side view of the composite closure 41 (band guard) with sealing element 43 on a vessel 45, in part as a sectional view;

(12) FIG. 11 shows a top view of composite fastener 41 (band guard);

(13) FIG. 12 shows an enlarged section of the cam screw closure of FIG. 2.

(14) FIGS. 1 and 3 show a cam screw closure 1. Cam screw closure 1 includes a metallic support 11 and a sealing element 3. In the illustration of FIG. 2, cam screw closure 1 is applied to a vessel 5. A curl 9 is formed at the lower end of cam screw closure 1. Several cams 7 are formed circumferentially distributed from curl 9. Cams 7 are formed by an axial deformation of curl 9 and extend radially further toward the center of the cam screw closure 1 than curl 9. Cam screw closure 1 shown in FIGS. 1 to 3 includes four cams 7, which are evenly distributed around the circumference. The sections shown in part in FIGS. 1 and 2 correspond to section III-III in FIG. 3.

(15) A channel 2 is formed in upper section 10 of carrier 11 near the radially outer end section of cam screw closure 1. Sealing element 3 is at least partially positioned in channel 2. In this embodiment, sealing element 3 is annular; in other embodiments, sealing element 3 may be disc-shaped, particularly if the diameter of the cam screw closure is small (e.g. at most 30 mm).

(16) To mediate adhesion between metallic carrier 11 and sealing element 3, an adhesive lacquer is typically applied to the side of metallic carrier 11 that is in contact with sealing element 3.

(17) In FIG. 2, cam screw closure 1 is applied to a vessel 5. Vessel 5 includes a vessel mouth 5a as the upper portion of vessel 5. The vessel mouth includes a thread 6 and an upper end 4 of vessel mouth 5a. Thread 6 is formed circumferentially in the area of vessel mouth 5a and extends circumferentially upwards or downwards (depending on the angle of view).

(18) To apply cam screw closure 1 to a vessel 5, cams 7 are brought into contact with sections of thread 6, and cam screw closure 1 is rotated clockwise relative to vessel 5. Due to the configuration of thread 6 and the interaction of cams 7 with thread 6, upper end 4 of vessel mouth 5a moves toward sealing element 3 during the rotational movement of cam screw closure 1 relative to vessel 5. A further rotational movement of cam screw closure 1 causes upper end 4 of vessel mouth 5a to press into and deform sealing element 3 so that a portion of upper end 4 of vessel mouth 5a is covered by sealing element 3, thereby closing vessel 5 tightly. In particular, a tight closure of vessel 5 is necessary to withstand increased pressure during thermal treatment of closed vessel 5 at temperatures above 70 C., 90 C. or even above 120 C.

(19) As shown in FIGS. 1 to 3, cam screw closure 1 includes a safety button 10b formed in upper portion 10 of carrier 11. Due to slope 10a in upper section 10 of carrier 11, safety button 10b tips toward the center of the vessel when there is a sufficiently large negative pressure in the vessel. Such a vacuum can be created by introducing water vapor into the vessel before closing the vessel with the closure.

(20) If a consumer opens the vessel by removing the vessel closure, the pressure in the vessel rises to ambient pressure and safety button 10b tips away from the center of the vessel. The tipping of safety button 10b is accompanied by a characteristic sound, by which a consumer can recognise that there was a vacuum in the vessel before it was opened.

(21) FIGS. 4 and 5 show a composite closure 61 (Combi-Twist) which, similar to cam screw closure 1 described above, can be attached to a vessel by a twisting motion and removed from the vessel via a twisting motion.

(22) Composite fastener 61 includes a carrier with an upper metallic section 71 and a plastic section 72 in an L-shape. A channel 78 is formed near the radial end of metallic section 71 of the carrier and a curl 77 is formed at the radial end of metallic section 71. A sealing element is at least partially positioned in channel 78.

(23) Several threaded elements 74a, 74b formed on the inside of plastic section 72 make contact with a mating thread in the region of the mouth of a vessel (not shown) to which composite closure 61 is to be attached. Furthermore, plastic section 72 of composite closure 61 includes a tamper-evident closure 73, which is similar in design to the tamper-evident closure shown in FIGS. 9 to 11 and is described in more detail with reference to FIGS. 9 to 11.

(24) If composite closure 61 is screwed onto a vessel by a twisting motion, a similar interaction of the vessel mouth of the vessel with the sealing element of composite closure 61 results as described for cam screw closure 1.

(25) FIGS. 6 to 8 show a press-on twist-off closure 21 (PT closure). PT fastener 21 includes a metallic carrier 31 with a curl 29 at the lower end of carrier 31 and a safety button 30a in upper section 30 of carrier 31.

(26) A sealing element 23 is formed both in the region of upper section 30 of carrier 31 and to a considerable extent on the apron of the beam, which extends downward from upper section 30 of carrier 31. PT closure 21, unlike cam screw closure 1 and composite closure 61, is pressed onto vessel mouth 25a when applied to a vessel 25. While pressing onto vessel mouth 25a, sealing element 23 is sufficiently soft to elastically enclose threaded elements 26 of vessel mouth 25a. Typically for this purpose, sealing element 23 is treated with steam before PT closure 21 is attached to a vessel 5 to cause the necessary softness of sealing element 23. After sealing element 23 has cooled, a mating thread in the form of an inverse of threaded elements 26 of the vessel mouth is formed in sealing element 23.

(27) An upper end 24 of vessel mouth 25a comes in contact with sealing element 23.

(28) To open receptacle 25, PT closure 21 is removed from receptacle 25 by a twisting motion.

(29) FIGS. 9 to 11 show a composite closure 41 (band guard) that works similar to PT closure 21 described above.

(30) Composite closure 41 includes a carrier with a metallic section 51 and a plastic section 52, a tamper-evident closure 53 and a safety button 50a. Tamper-evident closure 53 is configured to be removed from remaining composite closure 41 when composite closure 41 is removed from a vessel 45 and serves to allow a consumer to verify that composite closure 41 has already been removed from vessel 45. Safety button 50a is designed and works similarly to safety button 10b of cam screw closure 1.

(31) The plastic portion of composite closure 41 may include multiple axially extending indentations 56 to increase the stability of the closure.

(32) A sealing element 43 is arranged in composite closure 41 so that it comes into contact with both metallic section 51 and plastic section 52. To close a vessel 45, composite closure 41 is pressed onto vessel mouth 45a of vessel 45 so that at least upper end 44 of vessel mouth 45a comes into contact with sealing element 43.

(33) Plastic section 52 of the carrier includes multiple offset projections 54 that interact with threaded elements 46 of vessel mouth 45a. To open a vessel 45 closed by composite closure 41, composite closure 41 may be rotated relative to vessel 45.

(34) Distance h3 of a sealing element 3 between an upper end 4 of a vessel mouth 5a of a vessel 5 and the lower side of a support 11 of closure 1 is shown in FIG. 12, looking toward a cam screw closure 1, and described herein. Similarly, the distance (height) h3 must be determined for other closure types as well.

(35) Sealing element 3 clamped between vessel mouth 5 and support 11 of vessel closure 1 has a height h3 given when a vessel 5 is closed with closure 1. If height h3 is too low, there is a risk of sealing element 3 being cut through, which may impair the tightness of sealed vessel 5. If height h3 is too large, the tightness of the sealed vessel is impaired because the contact surface between upper end 4 of vessel mouth 5a and sealing element 3 is not sufficiently large. In order to achieve a suitable impression of upper end 4 of vessel mouth 5a into the sealing element, the composition of sealing element 3 is decisive.

EXAMPLES

(36) Examples of polymer compositions for sealing elements in a vessel closure are shown in Tables 1, 2 and 3. The examples are labelled with Ex. and a consecutive number for the respective example.

(37) The component designations shown in the tables stand for . . . .

(38) TABLE-US-00001 PAO-5 Polyalphaolefin with a kinematic viscosity of about 5 cSt at 100 C., PAO-65 Polyalphaolefin with a kinematic viscosity of about 65 cSt at 100 C., PAO-150 Polyalphaolefin with a kinematic viscosity of about 150 cSt at 100 C., PAO-300 Polyalphaolefin with a kinematic viscosity of about 300 cSt at 100 C., C4C2 Alpha-butene-ethylene copolymer with an alpha-butene content of more than 50 mol %, C4C3 Alpha-butene-ethylene copolymer with an alpha-butene content of more than 50 mol %, C2 Ethene homopolymer (LDPE), C3C2 Propene-ethene copolymer with a propene content of more than 50 mol %, C3C6 Propene-alpha-hexene copolymer with a propene content of more than 50 mol %, C4 Alpha-butene homopolymer.

(39) The polyalphaolefins (PAO-5, PAO-65, PAO-150, PAO-300) are commercially available from Chevron Phillips or from ExxonMobil (e.g. SpectraSyn series).

(40) The alpha-butene-ethylene copolymer has a Shore A hardness of 60 and a density of 0.870 g cm.sup.3.

(41) The alpha-butene-propene copolymer has a Shore A hardness of 87 and a density of 0.890 g cm.sup.3.

(42) The ethene homopolymer exhibits a Shore D hardness of 48 and a density of 0.928 g cm.sup.3.

(43) The density of the propene-ethylene copolymer is 0.900 g cm.sup.3.

(44) The propene-alpha-hexene copolymer exhibits a density of 0.900 g cm.sup.3.

(45) The alpha-butene homopolymer has a Shore D hardness of 54.

(46) TABLE-US-00002 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Component, % by weight PAO-5 4.8 9.1 16.7 9.1 PAO-65 9.1 PAO-150 9.1 PAO-300 9.1 C4C2 68.5 65.4 59.9 65.4 65.4 65.4 C4C3 87.2 C2 15.2 14.5 13.3 14.5 14.5 14.5 C3C2 7.6 7.3 6.7 7.3 7.3 7.3 C3C6 C4 Additive 3.9 3.7 3.4 3.7 3.7 3.7 3.7 Property Coefficient of 0.31 0.33 0.39 0.36 0.23 0.18 0.28 friction, dimensionless Total migration, 2.14 3.27 5.11 1.35 1.15 0.99 2.90 mg cm.sup.2 Oxygen transmission 662 809 1162 732 681 650 680 rate cm.sup.3 m.sup.2 d.sup.1 bar.sup.1

(47) TABLE-US-00003 TABLE 2 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 8 9 10 11 12 13 14 15 16 Com- ponent % by weight PAO-300 20.0 30.0 40.0 5.0 10.0 20.0 10.0 10.0 10.0 C4C2 90.9 85.9 75.9 61.9 61.9 61.9 C4C3 75.9 65.9 55.9 C2 24.0 C3C6 24.0 C4 24.0 Additive 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 % by weight

(48) TABLE-US-00004 TABLE 3 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 17 18 19 20 21 22 23 24 Component % by weight PAO-5 9.1 16.7 9.1 16.7 PAO-300 5.0 10.0 30.0 40.0 C4C2 65.4 59.9 65.4 59.9 65.9 55.9 C4C3 90.9 85.9 C2 14.5 13.3 14.5 13.3 C3C6 7.3 6.7 C4 7.3 6.7 Additive 3.7 3.4 3.7 3.4 4.1 4.1 4.1 4.1 % by weight

(49) Generally, no specific component is necessarily present in any of the polymer compositions or the polymer composition. Specifically, an increased occurrence of a component in the examples is not an indication that this component must necessarily be included in the polymer composition. Instead, components can be omitted from the compositions of the examples or replaced by other component(s). Components may also be added.