WO1997031834A1 - A screw cap of plastics material - Google Patents

A screw cap of plastics material Download PDF

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Publication number
WO1997031834A1
WO1997031834A1 PCT/EP1997/000835 EP9700835W WO9731834A1 WO 1997031834 A1 WO1997031834 A1 WO 1997031834A1 EP 9700835 W EP9700835 W EP 9700835W WO 9731834 A1 WO9731834 A1 WO 9731834A1
Authority
WO
WIPO (PCT)
Prior art keywords
annular
top wall
screw cap
seal
shoulder
Prior art date
Application number
PCT/EP1997/000835
Other languages
French (fr)
Inventor
Giacinto Torchio
Original Assignee
Alplast S.P.A.
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 Alplast S.P.A. filed Critical Alplast S.P.A.
Publication of WO1997031834A1 publication Critical patent/WO1997031834A1/en

Links

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
    • B65D41/045—Discs

Definitions

  • the present invention relates to a screw cap of plastics material for sealing bottles, particularly PET bottles for mineral water and carbonated drinks having a mouth diameter of 28 mm, or glass bottles of similar dimensions.
  • the cap according to the invention is of the type comprising a top wall, a threaded annular skirt terminating in a thinner portion which has an internal annular engagement rim and is intended to form a security ring, an annular shoulder disposed at the junction between the top wall and the annular skirt and extending inwardly so as to form an annular recess with the top wall, and a seal of plastics material disposed adjacent the end wall and comprising a central disc-shaped portion and a peripheral annular sealing rim retained by the annular shoulder, the seal being formed by compression- moulding m si tu by the deposition of a drop of plastics material in the cap and the pressing of the drop against the top wall with a heated punch so as to cause the plastics material to flow into the annular recess and against the shoulder.
  • the object of the present invention is to provide a cap of the aforesaid type which can achieve an effective seal in use without requiring too great a pressure to fit it on the bottle, and which requires a smaller quantity of plastics material to form the seal than is required with known caps.
  • the subject of the present invention is a cap of the aforementioned type having the characteristics defined by the following claims .
  • Figure 1 is a cross-section of a cap according to the invention.
  • Figure 2 is a detail of the portion indicated II in Figure 1 , on an enlarged scale.
  • a cap, indicated 1 of plastics material such as a propylene copolymer is usable in particular for sealing PET or glass bottles for mineral water and carbonated drinks having a mouth diameter of 28 mm.
  • the cap 1 comprises a top wall 2 and an annular skirt 3 with a screw thread 4.
  • the skirt 4 terminates in a thinner portion 5 with an internal annular engagement rim 6 for engaging beneath a collar of the bottle.
  • the portion 5 is intended to be notched peripherally in known manner in its upper portion, as indicated at 7, after the cap 1 has been fitted on the bottle, so as to form bridges 8 which constitute weakened connecting regions between the portion 5, which acts as a security seal, and the skirt 3.
  • the portion 5 is in fact separated from the skirt 3 as a result of the breaking of the bridges 8 when the cap is unscrewed from the bottle for the first time.
  • the cap At the junction between the top wall 2 and the skirt 3, the cap has an annular shoulder 9 which extends inwardly and comprises an mwardly-facmg annular surface and a downwardly-facing annular surface 9a.
  • the annular surface 9a comprises a horizontal portion which is spaced from the internal surface of the top wall 2 by a distance X which is between 1.80 and 1.94 mm and preferably 1.87 mm.
  • the annular shoulder 9 includes an annular rib 10 having a height Y which is between 0.50 and 0.65 mm and is preferably 0.62 mm.
  • the inwardly-facmg annular surface of the shoulder 9 forms a continuous annular recess 11 the surface of which comprises a first, upwardly-diverging frusto-comcal portion 12 which, in section, extends between the points indicated A and B, and a second portion constituted by a groove 13 which, in section, has a circular profile and extends between the points B and C.
  • the frusto-comcal portion 12 is inclined to the horizontal at an angle Z of between 55 and 65°, preferably of 60°, and the radius R of curvature of the groove 13 is between 0.55 and 0.69 mm and is preferably 0.62 mm.
  • a seal, indicated 14, of plastics material formed in si tu is disposed adjacent the top wall 2 of the cap.
  • the seal 14 is formed by compression-moulding by the deposition in the cap of a drop of thermoplastic material weighing about 0.16 g and the subsequent pressing of the drop with a punch heated to a temperature of between 60 and 70°C, so as to cause the plastics material to flow into the annular recess 11 formed by the inwardly-facing annular surface of the shoulder 9 between the rib 10 and the internal surface of the top wall 2.
  • the seal 14 has a thickness of 0.25 mm in its central portion, increasing to 0.35 mm at its peripheral rim.
  • the reduced weight of the drop of plastics material for forming the seal achieves a saving of material in comparison with the prior art without adversely affecting the sealing achieved by the seal.

Abstract

A screw cap of plastics material for sealing PET bottles having a mouth diameter of 28 mm has an annular shoulder (9) between the top wall (2) and the annular skirt (3) of the cap. The annular shoulder (9) includes an annular rib (10) and forms a continuous annular recess (11) engaged by the rim of a seal (14) which is compression-moulded in situ. The depth (Y) of the annular rib (10) is about 0.62 mm and the distance (X) between the downwardly-facing surface (9a) of the shoulder (9) and the internal surface of the top wall (2) is about 1.87 mm. The annular recess (11) comprises a first, upwardly-diverging, frusto-conical portion (12) with an inclination (Z) of about 60° and a second portion constituted by a groove (13) having, in section, a circular profile with a radius of curvature (R) of about 1.76 mm. The weight of the drop which is intended to form the seal (14) is about 0.16 g.

Description

A screw cap of plastics material
The present invention relates to a screw cap of plastics material for sealing bottles, particularly PET bottles for mineral water and carbonated drinks having a mouth diameter of 28 mm, or glass bottles of similar dimensions.
The cap according to the invention is of the type comprising a top wall, a threaded annular skirt terminating in a thinner portion which has an internal annular engagement rim and is intended to form a security ring, an annular shoulder disposed at the junction between the top wall and the annular skirt and extending inwardly so as to form an annular recess with the top wall, and a seal of plastics material disposed adjacent the end wall and comprising a central disc-shaped portion and a peripheral annular sealing rim retained by the annular shoulder, the seal being formed by compression- moulding m si tu by the deposition of a drop of plastics material in the cap and the pressing of the drop against the top wall with a heated punch so as to cause the plastics material to flow into the annular recess and against the shoulder.
The object of the present invention is to provide a cap of the aforesaid type which can achieve an effective seal in use without requiring too great a pressure to fit it on the bottle, and which requires a smaller quantity of plastics material to form the seal than is required with known caps.
In order to achieve this object, the subject of the present invention is a cap of the aforementioned type having the characteristics defined by the following claims .
The invention will now be described with reference to the appended drawings, provided purely by way of non-limiting example, in which:
Figure 1 is a cross-section of a cap according to the invention, and
Figure 2 is a detail of the portion indicated II in Figure 1 , on an enlarged scale.
A cap, indicated 1 , of plastics material such as a propylene copolymer is usable in particular for sealing PET or glass bottles for mineral water and carbonated drinks having a mouth diameter of 28 mm.
The cap 1 comprises a top wall 2 and an annular skirt 3 with a screw thread 4.
The skirt 4 terminates in a thinner portion 5 with an internal annular engagement rim 6 for engaging beneath a collar of the bottle.
The portion 5 is intended to be notched peripherally in known manner in its upper portion, as indicated at 7, after the cap 1 has been fitted on the bottle, so as to form bridges 8 which constitute weakened connecting regions between the portion 5, which acts as a security seal, and the skirt 3. The portion 5 is in fact separated from the skirt 3 as a result of the breaking of the bridges 8 when the cap is unscrewed from the bottle for the first time.
At the junction between the top wall 2 and the skirt 3, the cap has an annular shoulder 9 which extends inwardly and comprises an mwardly-facmg annular surface and a downwardly-facing annular surface 9a.
The annular surface 9a comprises a horizontal portion which is spaced from the internal surface of the top wall 2 by a distance X which is between 1.80 and 1.94 mm and preferably 1.87 mm.
The annular shoulder 9 includes an annular rib 10 having a height Y which is between 0.50 and 0.65 mm and is preferably 0.62 mm.
Between the rib 10 and the internal surface of the top wall 2, the inwardly-facmg annular surface of the shoulder 9 forms a continuous annular recess 11 the surface of which comprises a first, upwardly-diverging frusto-comcal portion 12 which, in section, extends between the points indicated A and B, and a second portion constituted by a groove 13 which, in section, has a circular profile and extends between the points B and C.
The frusto-comcal portion 12 is inclined to the horizontal at an angle Z of between 55 and 65°, preferably of 60°, and the radius R of curvature of the groove 13 is between 0.55 and 0.69 mm and is preferably 0.62 mm. A seal, indicated 14, of plastics material formed in si tu is disposed adjacent the top wall 2 of the cap.
The seal 14 is formed by compression-moulding by the deposition in the cap of a drop of thermoplastic material weighing about 0.16 g and the subsequent pressing of the drop with a punch heated to a temperature of between 60 and 70°C, so as to cause the plastics material to flow into the annular recess 11 formed by the inwardly-facing annular surface of the shoulder 9 between the rib 10 and the internal surface of the top wall 2.
The seal 14 has a thickness of 0.25 mm in its central portion, increasing to 0.35 mm at its peripheral rim.
It has been found in practice that, in a cap having a shoulder 9 with the dimensions described above, the seal 14 adheres well to the internal surface of the top wall 2 and has no tendency to lift from this wall.
The reduced weight of the drop of plastics material for forming the seal achieves a saving of material in comparison with the prior art without adversely affecting the sealing achieved by the seal.

Claims

1. A screw cap of plastics material for sealing plastics or glass bottles for mineral water and carbonated drinks having a mouth diameter of 28 mm, comprising:
- a top wall (2), an annular skirt (3) having a screw thread (4) and terminating in a thinner portion (5) which has an internal annular engagement rim (6) and is intended to form a security ring,
- an annular shoulder (9) disposed at the junction between the top wall (2) and the annular skirt (3) and comprising an inwardly-facing annular surface and a downwardly-facing annular surface (9a),
- the annular shoulder (9) including an annular rib (10) and forming, between the annular rib (10) and the internal surface of the top wall (2), a continuous annular recess (11 ) engaged by the peripheral rim of a seal (14) of thermoplastic material which is disposed adjacent the top wall (2) of the cap and is formed in si tu by compression moulding,
characterized in that
- the downwardly-facing annular surface (9a) of the annular shoulder (9) comprises a horizontal portion which is spaced from the internal surface of the top wall (2) by a distance (X) of between 1.80 and 1.95 mm,
- the annular rib (10) has a height (Y) of between 0.50 and 0.65 mm, - the annular recess (11 ) formed between the annular rib (10) and the internal surface of the top wall (2) comprises a first upwardly-diverging frusto-conical portion (12) inclined to the horizontal at an angle (Z) of between 55 and 65° and a second portion constituted by a groove (13) having, in section, a circular profile with a radius of curvature (R) of between 0.55 and 0.69 mm.
2. A screw cap according to Claim 1, characterized in that the distance (X) between the horizontal portion of the downwardly-facing annular surface (9a) of the annular shoulder (9) and the internal surface of the end wall (2)
Figure imgf000008_0001
3. A screw cap according to Claim 1, characterized in that the annular rib (10) of the annular shoulder (9) has a height (Y) of 0.62 mm.
4. A screw cap according to Claim 1, characterized in that the frusto-conical portion (12) of the annular recess (11) s inclined at an angle (Z) of 60° to the horizontal .
5. A screw cap according to Claim 1, characterized in that the seal (14) has a thickness of 0.25 mm in its central portion, increasing to 0.35 mm at its peripheral
6. A screw cap according to Claims 1 and 5, characterized in that the seal is produced by the deposition in the cap of a drop of thermoplastic material weighing about 0.16g and the subsequent pressing of this drop with a punch heated to a temperature of between 60 and 70°.
PCT/EP1997/000835 1996-03-01 1997-02-21 A screw cap of plastics material WO1997031834A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO96U000037 1996-03-01
IT96TO000037 IT239673Y1 (en) 1996-03-01 1996-03-01 SCREW CAPS OF PLASTIC MATERIAL

Publications (1)

Publication Number Publication Date
WO1997031834A1 true WO1997031834A1 (en) 1997-09-04

Family

ID=11414147

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1997/000835 WO1997031834A1 (en) 1996-03-01 1997-02-21 A screw cap of plastics material

Country Status (2)

Country Link
IT (1) IT239673Y1 (en)
WO (1) WO1997031834A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010028522A1 (en) 2010-05-04 2011-11-10 Robert Bosch Gmbh Screw cap for soft packaging

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2092999A (en) * 1981-01-16 1982-08-25 Metal Closures Group Plc Closure for screw-threaded container
EP0073334A1 (en) * 1981-07-24 1983-03-09 H-C Industries, Inc. Process and apparatus for making a closure
DE3606571A1 (en) * 1986-02-28 1987-09-03 Geyer Werkzeugbau Plastic screw cap
US4984703A (en) * 1989-10-03 1991-01-15 Owens-Illinois Closure Inc. Plastic closure with compression molded sealing liner
EP0637550A2 (en) * 1993-08-05 1995-02-08 Mcg Closures Limited Profiled liner for container closure

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2092999A (en) * 1981-01-16 1982-08-25 Metal Closures Group Plc Closure for screw-threaded container
EP0073334A1 (en) * 1981-07-24 1983-03-09 H-C Industries, Inc. Process and apparatus for making a closure
DE3606571A1 (en) * 1986-02-28 1987-09-03 Geyer Werkzeugbau Plastic screw cap
US4984703A (en) * 1989-10-03 1991-01-15 Owens-Illinois Closure Inc. Plastic closure with compression molded sealing liner
EP0637550A2 (en) * 1993-08-05 1995-02-08 Mcg Closures Limited Profiled liner for container closure

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010028522A1 (en) 2010-05-04 2011-11-10 Robert Bosch Gmbh Screw cap for soft packaging
WO2011138062A1 (en) 2010-05-04 2011-11-10 Robert Bosch Gmbh Screw closure for soft packagings

Also Published As

Publication number Publication date
ITTO960037U1 (en) 1997-09-01
IT239673Y1 (en) 2001-03-13

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