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
• • 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
  • B65D41/32—Caps or cap-like covers with lines of weakness, tearing-strips, tags, or like opening or removal devices, e.g. to facilitate formation of pouring openings
  • B65D41/34—Threaded or like caps or cap-like covers provided with tamper elements formed in, or attached to, the closure skirt
  • B65D41/3461—Threaded or like caps or cap-like covers provided with tamper elements formed in, or attached to, the closure skirt the tamper element being retracted by heat or by heat and pressure
  • B65D41/3466—Threaded or like caps or cap-like covers provided with tamper elements formed in, or attached to, the closure skirt the tamper element being retracted by heat or by heat and pressure and being integrally connected to the closure by means of bridges

Definitions

• COMPOSITE CLOSURE BACKGROUND OF THE INVENTION This invention relates to closures, and more particularly, to a composite plastic closure for bottles.
• metal crowns have been lined with various materials such as cork, rubber, thermosetting plastic and thermoplastic. Representative of the many crowns lined with such material are those shown in U.S. Patent Nos. 1,486,937, 2,548,305, 2,654,913, 2,684,774, 2,688,776, 2,696,318, 2,823,422, 2,834,498, 2,840,858, 2,952,035, 3,183,144, 3,278,985 and 3,300,072.
• plastic crowns and closures have been recognized.
• the physical characteristics and nature of plastics such as their melting and plastic deformation temperatures, and their resiliency, impact and compression strengths, at molding and refrigeration temperatures, present different structural problems in molding plastic closures than in metal closures.
• the wall thickness is confined to a limited range, i.e., the wall must be thin enough to permit axial removal and deflection of the threaded skirt of the closure from the plunger, but thick enough to support the necessary thread height and profile.
• the threads of conventional plastic closures are also limited to a certain amount of taper to permit deflection and removal of the threaded skirt from the plunger.
• An improved composite plastic closure for bottles and other containers has a plastic cap with novel liner-engaging pedestals that are adapted to provide a secure mechanical or thermal interconnection with a plastic liner.
• the liner-engaging pedestals extend from the top wall of the cap in an area bounded by the closure-skirt. Portions of the pedestals are spaced apart from each other to define spaces that receive the plastic liner.
• each of the pedestals has at least one portion that provides an overhang to interlockingly engage the liner.
• the overhang is mushroom-shaped.
• the pedestal includes fusible pedestals with heat concentration zones that are fused to the liner.
• each of the fusible pedestals is cylindrical with a circular edge that defines part of the heat concentration zone.
• each of the fusible pedestals has an apex that defines part of the heat concentration zone.
• such pedestals are pyramid-shaped.
• the closure is formed with an inwardly biased pilfer band that is detachably connected to the skirt.
• FIGURE 1 is a cross-sectional view of a composite plastic closure in accordance with principles of the present invention, that has been screwed onto a container to provide a fluid tight seal with its finish;
• FIGURE 2 is a bottom plan view of the underside of the cap of the composite closure with greatly magnified portions broken away for ease of clarity and understanding;
• FIGURE 3 is a greatly enlarged perspective view of some of the mushroom-shaped pedestals of the closure, with portions of the cap's top wall shown in cross-section;
• FIGURE 4 is a cross-sectional view of some of the mushroom-shaped pedestals of the cap;
• FIGURE 5 is a cross-sectional view similar to Figure 4, but showing the liner in interlocking engagement with the mushroom-shaped pedestals;
• FIGURE 6 is an enlarged cross-sectional view of another composite plastic closure having fusible cylindrical pedestals in accordance with principles of the present invention;
• FIGURE 7 is a greatly magnified perspective view of some of the fusible cylindrical pedestals of the composite closure of Figure 6;
• FIGURE 8 is a greatly magnified perspective view of some of the fusible pyramid-shaped pedestals of another composite plastic closure in accordance with principles of the present invention.
• a composite plastic closure 100 is provided to close and fluidly seal the finish of a threaded bottle 102 or other containers filled with a liquid, such as a carbonated beverage.
• Composite closure has a resilient plastic cap 104, which is sometimes referred to as a shell or crown, and has a resilient fluid-impervious plastic liner or seal 106.
• Cap 104 is preferably made of moldable thermoplastic, such as polypropylene or polyethylene. Other materials can also be used.
• Liner 106 is preferably made of moldable thermoplastic, such as polyvinyl chloride (PVC). Other liner materials, such as ethylene vinyl acetate (EVA) can also be used.
• the cap In order to increase the strength of the cap, the cap has spun plastic portions that provide a spiral molecular orientation, i.e., spirally orientated molecules 108.
• the spiral orientation gives the cap greater hoop strength and crack resistance than plastic caps formed without spiral orientation.
• the spun plastic material provides good impact strength and enables the cap to pass a drop test in the refrigeration temperature range of 32-40 degrees F.
• cap 104 is of a one-piece unitary construction and is made of a polypropylene homopolymer. All the parts and components of the plastic cap 104 are integrally connected to each other.
• the cap 104 has a top wall disc-shaped portion or surface 110 that is sometimes referred to as the "top,” and an annular peripheral skirt 112 depending from the top 110.
• Top 110 has a generally flat outer surface 110a and an inner surface that provides an underside 110b.
• the circular edge or corner 110c formed by the intersection of the top and the skirt is rounded or chamfered.
• skirt 112 has internal threads 114 and an internal annular lip 116 that provides a retainer to retain and confine the annular bead portion 106a of liner 106 and serves to support and seal against a cylindrical sleeve during the liner-forming process.
• annular bead portion 106a advantageously seals against the finish of the bottle to fluidly seal any irregularities, such as bumps or unevenness in the finish.
• Retainer 116 is inclined and converges radially inward away from top 110.
• the exterior surface of skirt 112 has circumferentially spaced vertical finger-gripping ribs 120 to facilitate gripping of the cap.
• the vertical ribs terminate in an outer rim 124 spaced below top 110.
• Rim 124 has an inwardly inclined annular shoulder 126 that provides the end skirt 112.
• a heat-shrinkable detachable pilfer-band or tamper-proof band 128 is provided at the end of the skirt by a plurality of frangible members or bridges 130.
• pilfer-band 128 When formed, pilfer-band 128 is biased radially inward from skirt 112 to provide a frusto-conical band having a minimum inside diameter that is less than the inside diameter of the skirt. The band is subsequently stretched, expanded and lifted to provide a circumferential or cylindrical portion having an inside diameter approximately equal to the inside diameter of the skirt 112 to enable the cap 104 to be inserted onto the container 102.
• the cylindrical band has a resilient memory and when reheated will assume its original frusto-conical shape.
• pilfer-band 128 is heated to shrink about and engage the bottleneck.
• pilfer-band 128 will fracture or break in selected areas.
• some of the frangible bridges 130 are thicker than others so that when the closure 100 is removed from the bottle, the pilfer-band will tear into one or more pieces and still be attached to the closure 100 by the thicker bridges. In some circumstances it may be desirable that the bridges 130 all have the same thickness and be only horizontally scored so that the pilfer-band 128 will remain on the bottle 102 when the closure 100 is removed.
• the cap has a plurality of liner-engaging pedestals 132 that interlockingly engage liner 106.
• Pedestals 132 extend vertically from the underside 110b of cap-top 110 to a position above the cap's annular lip 116. As shown in Figures 2-5, the pedestals 132 are spaced apart from each other in a grid-like array or matrix in longitudinal parallel rows and lateral parallel rows to define a plurality of liner-receiving passageways, channels or spaces 134 therebetween to receive the liner-forming plastic 106. Liner-receiving spaces 134 and pedestals 132 are circumferentially bounded and surrounded by skirt 112 ( Figure 1).
• Each pedestal 132 ( Figures 3-5) is formed with a generally upright, vertical body 136 extending in the upright (axial) direction.
• Pedestal-body 136 has a free end or head 138 that is spaced away from the top 110 of cap 104.
• pedestal-body 136 has a generally square cross-section.
• the free end 136 ( Figures 3-5) of pedestal-body 138 is upset, such as by compression and/or heating, to form a mushroom-shaped head with an overhang 140 that extends outwardly of the body 138 in a direction generally transverse to the upright direction.
• Overhangs 140 provide a mechanical interlock between pedestals 132 and liner 106.
• the holding strength of the pedestals and the tear strength of the mechanical connection between the liner 106 and pedestals 132 is proportional to the diameter and extent of the overhang 110 of pedestals 132, the number of pedestals 132 and the spacing 134 between pedestals.
• peel strength of the pedestals can be varied to a desired amount, such as between two and six pounds. This versatility is important because it permits the liner 106 to be detached or stripped from the pedestals 132 with a minimum amount of effort at a later time. The maximum bond and holding strength between the pedestals 132 and liner 106 occurs when the overhangs 140 of the pedestals contact each other.
• the liner 106 has a centrally disposed circular disc-shaped portion or membrane 106b ( Figure 1) that extends across and is connected to and circumscribed by an annular sealing bead 106a.
• Disc portion 106b engages the underside 110a of cap-top 110 and extends to a position beneath the mushroom-shaped heads 138 to completely cover and overlie pedestals 132.
• Annular bead 106a is confined in the channel between top 110 and retainer 116.
• the outer face of bead 106a has a rounded lower portion 142 ( Figure 6) that is shaped complementary to the internal rounded corner that connects the top 110 to skirt 112, and has an outer upper frusto-conical portion 144 that is inclined and converges radially inward away from top 110, and engages retainer 116.
• the inner face of bead 106a has a vertical lower portion or shoulder 146 and an upper frusto-conical sealing portion 148 that is inclined and diverges radially outward from shoulder 146.
• Upper sealing portion 148 resiliently seals and seats against the finish and rim of the bottle to abut against and fluidly seal any irregularities, such as bumps or unevenness, in the finish.
• thermoplastic liners 106 When certain types of thermoplastic liners 106 are used, such as EVA liners, the liner 106 is thermally fused and bonded to pedestals 132 ( Figure 5) as it is compression molded and heated during the liner-forming process. This provides a thermo- connection in addition to the mechanical interlock provided by the mushroom-shaped pedestals 132 ( Figure 5). For other materials, such as PVC, the liner may not be fused to the pedestals when it is compression molded and heated, but it is still securely mechanically held by the mushroom-shaped pedestals 132.
• the resultant secure mechanical interconnection between cap 104 and liner 106 attributable to the holding strength of the mushroom-shaped pedestals 132 permits the liner to be molded without heating the cap, or at least without heating the non-pedestal portions of the cap, to its melting and plastic deformation temperature, thereby minimizing distortion of the cap when the liner is formed.
• pedestals having heads or overhangs with other shapes could also be used to provide a mechanical interlock with the liner in accordance with principles of the present invention.
• FIG 6 is identical to the composite closure 100 shown in Figure 1, except that the pedestals 152 are in the form of fusible cylindrical pedestals and do not have an overhang.
• Each of the pedestals 152 ( Figure 7) has a generally planar or flat end 154 with a circular edge 156 that defines at least part of a fusible heat concentration zone, that becomes thermally fused to liner 106 ( Figure 6) when liner 106 is compression molded and heated in cap 104 during the liner-forming process.
• the thermal bond between liner 106 and pedestals 152 provide a solid thermal interconnection between liner 106 and cap 104.
• the shape and arrangement of the fusible pedestals 152 are such as to permit the pedestals to be heated to their melting and plastic deformation temperature for fusion with the liner 106, while the other portions of the cap 104 are kept cooler, thereby minimizing distortion of the cap when the liner is formed.
• Figure 8 is identical to the composite closure 150 shown in Figures 6 and 7, except that the fusible pedestals 162 are pyramid-shaped and the bases 164 of the pyramids 162 in each lateral row 166 are contiguous.
• the apex or peak 168 of each pyramid 162 and the portions immediately adjacent thereto provides a fusible heat concentration zone 170 that becomes thermally fused to the molten liner-forming plastic as the liner is compression molded and heated in the cap during the liner-forming process.
• the fusible pyramid-shaped pedestals 162 also permit the pedestals to be heated to their melting and plastic deformation temperature for fusion to the liner 106, while the other portions of the cap are kept cooler so as to minimize distortion of the cap 104 when the liner is formed. Because of the shape, arrangement and high heat transfer capabilities of the pyramid-shaped pedestals 162, it is believed that the cap with pyramid-shaped pedestals 162 can be kept even cooler than a cap with cylindrical pedestals 152, when the liner is formed.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Closures For Containers (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=22138823

Family Applications (1)

Country Status (7)

Cited By (6)

Families Citing this family (9)

Citations (5)

Family Cites Families (18)

• 1980
  • 1980-09-08 BR BR8008835A patent/BR8008835A/pt not_active IP Right Cessation
  • 1980-09-08 WO PCT/US1980/001143 patent/WO1981000838A1/en unknown
  • 1980-09-08 JP JP55502288A patent/JPS6344627B2/ja not_active Expired
  • 1980-09-08 MX MX18384180A patent/MX151062A/es unknown
  • 1980-09-19 DE DE8080105619T patent/DE3070923D1/de not_active Expired
  • 1980-09-19 EP EP19800105619 patent/EP0025991B1/en not_active Expired
  • 1980-09-19 AR AR28259980A patent/AR226863A1/es active
• 1986
  • 1986-07-02 JP JP61154307A patent/JPS62122964A/ja active Pending

Patent Citations (5)

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