EP0168982A1 - Pre-threaded container closure - Google Patents

Pre-threaded container closure Download PDF

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Publication number
EP0168982A1
EP0168982A1 EP85304379A EP85304379A EP0168982A1 EP 0168982 A1 EP0168982 A1 EP 0168982A1 EP 85304379 A EP85304379 A EP 85304379A EP 85304379 A EP85304379 A EP 85304379A EP 0168982 A1 EP0168982 A1 EP 0168982A1
Authority
EP
European Patent Office
Prior art keywords
gasket
closure
container
corner
neck
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP85304379A
Other languages
German (de)
English (en)
French (fr)
Inventor
Kenneth Martin Sinnott
John Richard Knight
Geoffrey Richard Thwaites
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
WR Grace and Co Conn
WR Grace and Co
Original Assignee
WR Grace and Co Conn
WR Grace and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by WR Grace and Co Conn, WR Grace and Co filed Critical WR Grace and Co Conn
Publication of EP0168982A1 publication Critical patent/EP0168982A1/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D41/00—Caps, e.g. crown caps or crown seals, i.e. members having parts arranged for engagement with the external periphery of a neck or wall defining a pouring opening or discharge aperture; Protective cap-like covers for closure members, e.g. decorative covers of metal foil or paper
    • B65D41/02—Caps or cap-like covers without lines of weakness, tearing strips, tags, or like opening or removal devices
    • B65D41/04—Threaded or like caps or cap-like covers secured by rotation
    • B65D41/0435—Threaded or like caps or cap-like covers secured by rotation with separate sealing elements
    • B65D41/0442—Collars or rings

Definitions

  • the present invention relates to a pre-threaded container closure, of the type serving as a screw cap for engagement on a neck of the container, for example the neck of a bottle.
  • Pre-threaded container closures are known in two main forms, the metal screw cap and the injection moulded plastic screw cap.
  • plastic caps are disclosed in GB-A-2,116,529 and in WO-A-82/02182.
  • the gaskets are aimed at achieving high compression of the gasket material around the outside corner of the bottle neck rim.
  • the present invention envisages the surprising step of using a flowed in gasket and achieving a seal which requires no gasket composition in contact with the outer corner of the container rim, and instead employs a particular profile to the container, and/or the gasket, and/or the closure to proviae for adequate sealing action on tne inner corner of the container neck as the closure is screwed on.
  • One aspect ot tne present invention provides a process of closing a container having an externally tnreaaea neck, comprising: taking a container closure of a first plastics material, having an end panel, an internally threaded skirt, and a separately formed gasket of a softer second plastics material on the end panel and screwing tnat pre-threaded closure onto the container neck to close tne container neck, to achieve sealing contact of tne end of the container neck rim without contact of the material of said gasket against the outer corner of the bottle neck rim, characterised in that the gasket is a flowed in gasket applied to tne pre-threaded closure without moulding, before the closure is itself applied to tne container.
  • a second aspect of the present invention provides a plastic pre-threaded container closure having a separately formed gasket of a plastics material softer tnan tnat of the closure, the gasket having a surface configuration such tnat its surface is further from the median plane of the end plane of the closure at a radially inner location than it is at a radially outer location, whereby the gasket seals against the,inner corner of the container neck rim without contact of gasket composition against the outer corner of the container neck rim, characterised in that the gasket is a flowed-in gasket formed without moulding.
  • a third aspect of the present invention provides a pre-threaded plastic container closure having an internally threaded skirt, ah end panel, and a separately formed gasket, characterised in that the gasket is a flowed in gasket applied to the closure without moulding; and in that the end panel includes a rib embedded in the flowed in gasket to generate localised increased compression of the gasket material in an annular region thereof adjacent to the location of the internal corner of the neck rim of a container on which the closure is to be used, so the flowed in gasKet seals against the internal corner of the container neck rim substantially without contact between the gasket and the outer neck rim corner.
  • a fourth aspect of the invention provides, in combination, a container having a threaded neck; and a plastic closure having an end panel bearing a separately formed plastic gasket of a material softer than that of the closure, and an internally threaded skirt joined to said end panel for engaging the container neck; the end of the container neck being shaped to encourage movement of the gasket composition radially inwardly of tne end panel during closing of the container using that cap, to effect a seal on tne inside corner of the container neck, characterised in that the gasket is a flowed in gasket applied to the closure without moulding.
  • the flowed in gasket is formed of a hot melt composition applied to the closure in molten form and allowed to solidify quickly on cooling.
  • the step of relying on sealing at the inside corner of the container neck is a very surprising one to take unless the material of the cap is relatively rigid, or the cap end panel is very thick, because of the natural expectation that the "doming" of the cap will have the effect of relaxing gasket compression where the compression arises at the inside corner, despite the fact that gasket compression at the outside corner is substantially unaffected by doming.
  • the dangers of such doming are discussed in WO-A-82/021282, on page 2, lines 7 to 30.
  • an accurately moulded gasket would be expected to be necessary in order to ensure the precise placement of the gasket and the accuracy of engagement of the gasket into the container neck.
  • cap 1 shown in Figure 1 has a gasket 2 positioned in the vicinity of the corner between the cap end panel 3 and the cap skirt 4 so that, as the cap 1 is screwed onto a bottle neck 5, the gasket 2 becomes pressed into sealing contact with the outside corner 6 of the bottle neck.
  • imperfections in the glass and in particular damage caused by previous "trips" of a returnable bottle cause problems with regard to this corner placement which is conventional in the art.
  • Figure 2 shows a first embodiment of a cap, again referenced 1, in accordance with the present invention.
  • the gasket 2 is confined in a recess whose floor 8 slopes in a direction such that it is further from the median plane 3a of the end panel 3 of the cap at the radially inner portion near an inner gasket-containment bead 9 than it is at its outer portion near the corner between the end panel 3 and the skirt 4.
  • the free surface of the gasket which contacts the bottle neck rim 5 as the bottle is closed, also slopes in the same way in relation to the median plane of the end panel 3.
  • the gasket 2 is formed by being flowed in to occupy the space defined between the inner gasket-containment bead 9 and an outer gasket-containment bead 10, and the gasket composition adopts the illustrated profile upon cooling.
  • the gasket 2 initially makes contact with the top of the bottle neck rim but the inclination of the surface of the gasket 2-is such that the gasket composition moves down onto the inner corner 7 of the bottle neck to provide the required "inner corner seal” action.
  • Figure 3 shows an alternative form of the gasket in which the gasket 2 assumes the distinctly toroidal configuration by virtue of the high viscosity of the flowed in composition, and is held in the flat-bottomed gasket-receiving groove by means of the undercut of the inner gasket-containment bead 9 of Figure 2, and an undercut 11 in place of the outer gasket-containment bead 10of Figure 2.
  • the slope of the surface of the gasket 2 is entirely due to the thickness of the gasket and is such tnat as the bottle cap is screwed down onto the bottle neck, the shape of the gasket 2 and the shape of the bottle neck 5 co-operate to shift the gasket composition down towards tne inner corner 7 of tne glass neck rim.
  • the neck configuration and the gasket shape co-operate to give the desired "inner corner seal" action.
  • Figure 4 shows a further flowed in gasket 2 in a cap 1 having a rib 13 formed in the floor of the gasket-receiving groove between the inner gasket-containment bead 9 and the outer gasket-containment bead 10 analogous to those of Figure 2.
  • the gasket has a free surface which has a slight inclination in the same direction as that shown in Figure 2, this embodiment relies heavily on the rib 13, embedded in the gasket, to ensure that there will be higher compression of the gasket material between the rib 13 and the end face of the bottle neck near the inner corner 7 of the neck rim, giving the desired result of high gasket compression at the inner corner and some shifting of composition around onto the inner corner for sealing thereon.
  • gasket prefferably has a relatively flat configuration and for at least part of the profiling to give the desired "inner corper seal" action to be derived from the shape of the glass finish itself.
  • each of the embodiments of Figures 2 to 4 has a configuration in which there is contact of the gasket with part of the end face of the bottle neck but pronounced sealing contact around the inner corner 7 of the bottle neck without, in any of these embodiments, any substantial contact between the gasket 2 and the outer corner (referenced 6 in Figure 1) of the neck rim. Hence if there is any roughening of the outer corner 6, or the evidence of chipped regions of that corner, there will be no appreciable increase in application torque and removal torque.
  • the hot melt composition used for forming the gasket was placed in two alternative placements in identical caps, one corresponding to the"outer corner seal” action illustrated in Figure 1, and the other corresponding to the "inner corner seal” action typical of Figures 2 to 4.
  • the venting pressure values as tested by means of an Owens Illinois “Secure Seal Tester” are set out in the third column for the "outer corner seal” placement of Figure 1 and in the fourth column for the "inner corner seal” placement in accordance with the present invention.
  • the venting pressure values quoted are measured in pounds per square inch but with the "S.I.” value measured in KPa shown in brackets alongside the imperial value.
  • the bottom line of the table quotes the average film weight of the gasket and shows that a slight reduction in the film weight was acnieved with the "inner corner seal" placement shown in the fourth column despite the fact that the venting pressure results were more consistent in that case.
  • bottles numbers 4 and 8 were so badly damaged that there was no seal achieved with the "outer corner seal" placement of Figure 1. Furthermore, bottles 5 and 7 achieved only a low venting pressure result (bearing in mind that venting pressures in excess of 150 lb/in 2 (1034 kPa) are considered acceptable for pressure holding applications).
  • Example 1 the test of Example 1 was used with a set of ten polyethylene terephthalate plastic finish samples. Because plastic bottles are not normally reusable, only the inner corner placement was used and, as shown from Table 2 below, the results were acceptable.
  • the normal criterion for commercially acceptable plastic bottles is for the closure to hold a pressure of at least 100 lb/in 2 (689 kPa) and for the closure not to be ejected from the container neck at a pressure of 150 lb/in 2 (1034 kPa). All ten samples listed in Table 2 below satisfy this requirement.
  • gasket can be formed by any one of several different methods, many of which are illustrated in the drawings.
  • a hot melt composition in accordance with our EP-A-0,129,309 and EP-A-0,129,310 may be flowed into the gasket-receiving groove of the pre-formed cap and distributed throughout the groove by spinning of the cap and whereupon the cooling of the composition causes it to adopt the desired configuration of the finished gasket.
  • a gasket may, if desired, be formed using the method of our GB-B-2,051,660 relating to microwave heating of the plastisol to form the gasket with separate non-microwave heating of the closure to enhance uniformity of heating of the plastisol.
  • the flowed in gasket may, if desired, be of a foamable composition so that the gasket material can be caused to foam upon heating, for example as disclosed in published GB-A-2,116,473.
  • Figure 3 may be formed by flowing in a high viscosity thermoplastic melt whose viscosity will then cause the resulting bead of the melt to adopt the Figure 3 generally toroidal configuration which it will retain on cooling.
  • the present invention is particularly suitable with returnable glass bottles, it may be applied to other containers, for instance plastic containers such as bottles.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Closures For Containers (AREA)
EP85304379A 1984-07-18 1985-06-19 Pre-threaded container closure Withdrawn EP0168982A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8418304 1984-07-18
GB08418304A GB2161797B (en) 1984-07-18 1984-07-18 Pre-threaded container closure

Publications (1)

Publication Number Publication Date
EP0168982A1 true EP0168982A1 (en) 1986-01-22

Family

ID=10564059

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85304379A Withdrawn EP0168982A1 (en) 1984-07-18 1985-06-19 Pre-threaded container closure

Country Status (6)

Country Link
EP (1) EP0168982A1 (ja)
JP (1) JPS6133949A (ja)
AU (1) AU586429B2 (ja)
GB (1) GB2161797B (ja)
NZ (1) NZ212593A (ja)
ZA (1) ZA854925B (ja)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0219265A2 (en) * 1985-10-08 1987-04-22 W.R. Grace & Co. Plastic container closure with moulded liner
FR2686065A1 (fr) * 1992-01-14 1993-07-16 Sincoplas Dispositif d'obturation de flacon avec joint d'etancheite.
DE9400507U1 (de) * 1994-01-13 1994-02-24 Kunststoff Technik Helmstedt G Schraubverschluß
WO1999058410A1 (fr) * 1998-05-13 1999-11-18 Crown Cork & Seal Technologies Corporation Bouchon a vis presentant une gorge destinee a recevoir un joint et moule pour realiser un tel bouchon

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4700860A (en) * 1986-03-31 1987-10-20 Owens-Illinois, Inc. Tamper indicating vacuum package
ZA882059B (ja) * 1988-03-22 1988-09-06
US20090236354A1 (en) * 2005-12-06 2009-09-24 Brasilata S/A Embalagens Can closure arrangement
GB2589711B (en) * 2018-12-17 2021-09-15 Crown Packaging Technology Inc Low migration container
GB2579839B (en) * 2018-12-17 2021-09-15 Crown Packaging Tech Low migration container

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1920286A (en) * 1931-07-21 1933-08-01 Hazel Atlas Glass Co Two-piece jar closure
GB1148089A (en) * 1966-08-29 1969-04-10 Armstrong Cork Co Sealed container with crown closure
GB1224733A (en) * 1967-03-31 1971-03-10 Kork N Seal Ltd Container closures with sealing liners
GB2051660A (en) * 1979-06-11 1981-01-21 Grace W R & Co Method of forming sealing gaskets in container closures
GB2116529A (en) * 1982-03-10 1983-09-28 Grace W R & Co Screw closure

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB817415A (en) * 1957-03-12 1959-07-29 Kork N Seal Ltd Improvements in or relating to closures for receptacles
FR710016A (fr) * 1931-01-03 1931-08-18 Fermeture de bouteille
GB801925A (en) * 1956-05-01 1958-09-24 Containers & Closures Ltd A new or improved closure cap
GB1172964A (en) * 1967-01-27 1969-12-03 Armstrong Cork Co Container and Linerless Closure Combination
FR2306895A1 (fr) * 1975-04-07 1976-11-05 Freda Tullie Capsule, en particulier pour la fermeture de recipients pourvus d'un goulot filete

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1920286A (en) * 1931-07-21 1933-08-01 Hazel Atlas Glass Co Two-piece jar closure
GB1148089A (en) * 1966-08-29 1969-04-10 Armstrong Cork Co Sealed container with crown closure
GB1224733A (en) * 1967-03-31 1971-03-10 Kork N Seal Ltd Container closures with sealing liners
GB2051660A (en) * 1979-06-11 1981-01-21 Grace W R & Co Method of forming sealing gaskets in container closures
GB2116529A (en) * 1982-03-10 1983-09-28 Grace W R & Co Screw closure

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0219265A2 (en) * 1985-10-08 1987-04-22 W.R. Grace & Co. Plastic container closure with moulded liner
EP0219265A3 (en) * 1985-10-08 1988-02-24 W.R. Grace & Co. Plastic container closure with moulded liner
FR2686065A1 (fr) * 1992-01-14 1993-07-16 Sincoplas Dispositif d'obturation de flacon avec joint d'etancheite.
EP0552086A1 (fr) * 1992-01-14 1993-07-21 Societe Industrielle Et Commerciale De Matieres Plastiques - Sincoplas Dispositif d'obturation de flacon avec joint d'étanchéité annulaire
DE9400507U1 (de) * 1994-01-13 1994-02-24 Kunststoff Technik Helmstedt G Schraubverschluß
WO1999058410A1 (fr) * 1998-05-13 1999-11-18 Crown Cork & Seal Technologies Corporation Bouchon a vis presentant une gorge destinee a recevoir un joint et moule pour realiser un tel bouchon
FR2778641A1 (fr) * 1998-05-13 1999-11-19 Crown Cork & Seal Tech Corp Bouchon a vis presentant une gorge destinee a recevoir un joint et moule pour realiser un tel bouchon

Also Published As

Publication number Publication date
AU4480985A (en) 1986-01-23
GB8418304D0 (en) 1984-08-22
JPS6133949A (ja) 1986-02-18
ZA854925B (en) 1986-02-26
GB2161797B (en) 1987-08-12
GB2161797A (en) 1986-01-22
NZ212593A (en) 1987-06-30
AU586429B2 (en) 1989-07-13

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

17P Request for examination filed

Effective date: 19860120

17Q First examination report despatched

Effective date: 19861008

D17Q First examination report despatched (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19871027

RIN1 Information on inventor provided before grant (corrected)

Inventor name: KNIGHT, JOHN RICHARD

Inventor name: THWAITES, GEOFFREY RICHARD

Inventor name: SINNOTT, KENNETH MARTIN