MXPA98003583A - Plast closure - Google Patents

Abstract

The present invention relates to a plastic closure for a container, the closure is characterized in that it comprises: a base wall, a peripheral skirt having an inner surface and a central locking shaft, means of interengaging on the inner surface of the skirt for coupling a container, the base wall has a substantially flat inner surface, a coating compression molded onto the inner surface of the base wall, the coating has a periphery with a peripheral edge radially inwardly repaired from the peripheral skirt and the means of interengagement on the skirt, the periphery of the coating includes an outer surface axially spaced from the base wall, the outer surface is inclined inwardly in the direction of the axis of the closure and axially away from the base wall, the outer surface inclined on the The periphery of the coating extends continuously from the edge pe of the cladding at a constant angle radially and axially of the wall of the wall

Description

PLASTIC CLOSURE FIELD OF THE INVENTION This invention relates to plastic closures used in glass or plastic containers.

BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION It has been described that in order to provide an appropriate seal it is necessary that there be a seal on the upper surface of the container, as well as on the outer cylindrical surface of the end or neck of the container. Thus, in compression molded liners a satisfactory seal has been provided, as shown for example in US Patent Nos. 4,378,893, 4,407,422 and 4,418,828, which are incorporated herein by reference. In these patents, the closure is provided with an annular lip that is spaced from the base wall and that defines an annular recess or channel and a plastic seal liner is compression molded such that it is held in place REF: 27462 • by integral projections which engage the liner, which are on the base wall and the annular lip to form a liner having an annular sealing rim that engages the outer wall surface of the container. In another type of closure for plastic beverage containers, shown in U.S. Patent Nos. 4,462,502 and 4,658,976, a circular liner is provided, resilient and flexible, which can rotate relative to the closure and which has a diameter greater than the outer diameter of the container lip. An annular projection is provided at the joint of the base wall and the skirt or side wall of the closure, and preferably has a configuration, when seen in cross section, having a horizontal portion, a vertical portion and a convex portion connecting the horizontal and vertical portion, a with the other, to provide a seal along a lateral, cylindrical, lateral surface of the neck edge of the container. In each of the structures mentioned above, the structure is based on the Flexible 25 of the base wall, of the closure, for increase the lateral sealing of the cylindrical surface of the container neck. In US Patents Nos. 5,265,747 and 5,462,187 a closure for a plastic beverage container is described, comprising a base wall, a peripheral skirt and a plurality of threads on the inner surface of the skirt, for coupling with the threads from a container that can be made of glass or plastic. The plastic closure includes a compression molded seal that extends around the periphery of the inner surface of the base wall and the attachment of the base wall to the peripheral skirt. The closure includes an axially thickened central portion; a channel surrounding the thickened portion and extending radially to a radially thickened annular portion, which is on the skirt, at the junction with the base wall. A concave surface extends from the base of the channel and joins the surface of the annular portion. A compression molded liner is provided over the thickened portion, channel and concave surface of the closure and defines a flat surface of # sealing to make contact with the end surface of the container neck, and an arcuate surface for engaging the arched surface of a container. In another form, the inner surface of the end wall has a uniform thickness and the flat surface and the surfaces receiving the annular liner are coplanar. In another form, the skirt of the closure has a radially thickened portion, on its interior surface on which a portion of the liner extends. In closures that are to be used with oil, a closure having a base wall with a peripheral skirt has been used. internal threads and the base wall is in flat position with respect to a compression-molded liner, of uniform thickness, which is on it. The lining is attached to a flat upper surface of the neck and to the edge inside the neck, but does not engage the outer surface or the outer edge of the collar. The closures described above have linings that are compression molded about closures. In the molding process * compression, the molten plastic granules are supplied to the interior of the closure and tools are introduced for the formation of the closure, inside the closure and the area within which the lining is to be formed is sealed in order to isolate it from the areas remaining of the closure that include the threads. If the closure of the area is not achieved, the molten plastic material may splatter the area of the # 10 closure, or the lining material may not form uniformly in the closure, for example, creating an excess of material on one side and an empty space on the opposite side of the closure. In those cases the plastic closure must be scraped. Among the objectives of the present invention are to provide a closure of * plastic and a method to make the closure, where the plastic closure has a such that the plastic closure provides an effective seal in glass and plastic containers, while at the same time providing a positive cut or seal; Where there is a more uniform flow of material for the liner, during compression molding, * whereby spatter or empty spaces are eliminated; which can be used as a vacuum closure for containers filled with hot contents; which can be used as a closure for containers filled with cold, non-carbonated liquids; and that can be used for containers containing carbonated liquids. In accordance with the invention, the plastic closure for a container having a termination on a top surface portion, a cylindrical outer surface portion, and a curved portion at the junction of the upper surface portion and the outer surface portion. The closing includes a base wall, a peripheral skirt having an inner surface and threads on the inner surface of the skirt, for engaging the container. The base wall has a flat interior surface and a lining compression molding is compression molded and attached to the flat surface of the plastic closure. The liner has a periphery spaced radially inward from the peripheral skirt and the skirt thread. The peripheral portion of the liner has a sloping surface, annular, exterior. The inclined surface tapers radially inwardly, away from the base wall of the closure and is positioned to engage the upper surface portion of the neck and the inner surface of the container and outwardly engaging with the outer surface of the container neck . The plastic closure is manufactured by forming a closure with a base wall that has a flat inner surface and a liner is compression molded on the flat surface of the plastic closure. The step of the compression molding of the lining is carried out in such a way that the lining is formed with a periphery spaced radially inward from the peripheral skirt and the thread that is on the skirt, as well as from the outer surface of the neck. The step of forming the liner includes forming the peripheral portion of the liner in a form such that it has an outer surface that is positioned to engage the upper surface portion of the neck and the inner edge of the container and that is out of engagement with the outer surface of the container.

DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective, fragmentary view of a container that comprises a plastic closure for carbonated drinks, and a container embodying the invention.

Figure 2 is a fragmentary vertical sectional view taken on an enlarged scale.

Figure 3 is a fragmentary, vertical sectional view of a portion of Figure 2, on an enlarged scale.

Figure 4 is a fragmentary sectional view of a portion of Figure 3, on a larger scale. Figure 5 is a fragmentary sectional view of the closure shown in Figure 4, without the container in place.

Figure 6 is a sectional view, fragmentary, similar to that of Figure 5, showing the closure before compression molding the liner, instead.

Figure 7 is a diagrammatic view of the plastic closure and container, showing the fit of the liner up to manufacturing tolerances in the neck of the container. * 10 Figure 8 is a plan view, of the bottom, of the closure shown in Figure 6.

Figure 9 is a fragmentary sectional view, on an enlarged scale, of a modified form of a container.

Figure 10 is a fragmentary sectional view taken from the left in Figure 9. Figure 11 is a fragmentary sectional view, on an enlarged scale, of another form of container.

Figure 12 is a sectional view, partial, fragmentary, of tools used for the compression molding of the lining, in a closure.

DESCRIPTION OF THE PREFERRED MODALITY Referring to Figures 1-8, the package embodying the invention comprises a plastic closure 20 threaded onto a container C, which is shown herein as a plastic container. The closure 20 is made of thermoplastic material such as polypropylene or polyethylene, for glass and plastic containers, including containers that are made of PET (for example, the container). The plastic closure 20 includes a base wall 22 and an annular, peripheral skirt 24, joined by an arcuate wall 26. The base wall 24 has a substantially uniform thickness throughout its extension, and defines a flat surface, inside, 28, to receive a liner 30. The arcuate portion 26 has substantially the same thickness as the base wall 22. A liner 30 of resilient material is molds by compression i n s i t u on the * inner surface 28. Liner 30 has a substantially uniform thickness. The liner 30 has a smaller diameter than the diameter of the skirt portion 24 axially adjacent the liner 30, whereby an annular space S is defined. The liner 30 includes an annular surface 32, tapered or inclined, on the periphery of lining 30 tapering or tilting * 10 radially inwardly and axially away from the base wall 22 of the plastic closure 22. The plastic closure 20 includes the thread 34 on the inner surface of the skirt 22 which engages the thread 36 which is on the neck F of the container C. The liner material can comprise any known material that can be extruded and cut to provide changes for compression molding in an apparatus such as shown, for example, in US Patents 3,955,605, 4,080,136 and 4,277,431. The liner material must also conform to other closure requirements, which include removal torques satisfactory, retention of carbonation, retention of carbonation under maximum load and satisfactory operation in a container when subjected to cycles through environmental changes of temperature and humidity. A satisfactory material is a mixture of an ethylene vinyl acetate composition and a thermoplastic elastomer composition, such as that of U.S. Patent No. 4,984,703 incorporated herein by reference. & 10 reference. This composition will work satisfactorily for both glass containers and plastic containers. Other types of materials that work satisfactorily for certain types of Containers are ethylene vinyl acetate compositions, thermoplastic elastomer compositions and thermoplastic compositions.

The plastic closure 20 is also preferably provided with a band B which indicates whether the cap has not been violated, which may be of any well known type, but is preferably that which is shown and claimed in US Patent No. 5,090,788, incorporated by reference. The band which indicates if the plug has been violated, is ^ attached to the skirt by a plurality of weakened portions defining a line of rupture. An annular rim extends axially upwardly and inwardly from the band that indicates whether the cap has been breached, towards the base wall of the closure and comprises a first portion of continuous annular ridge, connected to the band by an articulated portion and a second portion that has free ends * 10 of the segment portions that engage below the rim on the container when the closure is screwed into the container. In one form, the second portion comprises a plurality of segment portions, extending to up and into the first continuous portion. In another form, the second portion comprises a second continuous flange portion. The flange is bent in the middle of its ends so that the second portion is extend inward at a greater angle than the first portion of continuous flange. Other types of bands indicating plug violation may also be used, as is well known in the art. 25 In use, the plastic closure 20 is applies to a container C after it has been filled and the closure is screwed onto the neck F at a certain predetermined value of the torque. When a user wishes to access the drink, the user unscrews the closure, causing the band that indicates if the cap has been broken, to break. As the closure is unscrewed, the seal is first released and then the contents are vented, before the threads are uncoupled. As shown in Figures 2-4, when the closure 20 is fully applied to the neck F of the container C, the inclined outer surface 32 that is on the periphery of the liner 30 engages the upper surface 38 of the neck F and the edge inside 40 of the neck F, but does not engage the outer surface or the outer edge E of the neck F. The free edge 42 of the liner 30 defines a diameter that is smaller than the outside diameter of the neck F such that the seal it is confined to the r and r part of the inner portion of the upper surface 38. The main sealing force is found in the inner edge 40. fk As shown in Figure 7, which is a diagrammatic view, the closure incorporating the invention is capable of accommodating tolerances in glass and plastic containers, providing a satisfactory seal. The lines show the nominal dimension Pi, the maximum dimension P2 and the minimum dimension P3. The angle that the inclined surface 32 forms with a plane that is at an angle * 10 straight with respect to the axis of the closure, varies between a degree, as a minimum, up to fifteen degrees, as a maximum. Very satisfactory results have been achieved when the angle is approximately four degrees. Preferably, the angle should be between approximately four degrees and ten degrees. The type of closure shown in Figures 1-8 has a relatively thin base wall 22, so that it can is used as a vacuum closure on a container filled with a hot content, and when the contents are cooled, the base wall 22 is flexed axially inwardly to provide visual characteristics that if indicate if the plug has been violated. When the • closure is unscrewed from the container, the base wall flexes to its non-stressed condition. A vacuum closure like that must meet test requirements that include 5 vacuum retention; torque on the belt, wet and dry; zero leaks; twisting torque when removed; visual flexion; drip tests; maximum load test; vibration tests; submission to cycles of temperatures; venting tests; and performance of the band that indicates if the apón has been violated, if said band is used. In the form of the invention shown in Figures 9 and 10, the package is used for carbonated drinks. Accordingly, the base wall 22b of the closure 20b is made thicker to support the pressure of carbonated beverages. The package further includes the interrupted thread 36b which defines the conduits 37 for axial vent, on thread 36b, in a manner well known in the art. The liner 30b has an outer surface like the one shown in Figures 1-8. The liner 30b includes a sloping surface, peripheral, exterior, 32b, and a peripheral edge 42b. The lining 30b F includes an interior surface 50 that tapers inwardly and outwardly and extends along a complementary surface 52 on the base wall 22b of the closure 20b. The surface 32b engages the upper surface 38b of the neck and the inner edge 40b of the neck, and is not in engagement with the outer edge E of the neck F. The free edge 42b of the liner 30b defines a smaller diameter than the outside diameter of the neck such that the seal is confined to most of the inner portion of the neck. It has been found that plastic closure, when used for carbonated drinks, works satisfactory for beverage containers for closures and containers. In the form shown in Figure 11, the package is also used for carbonated beverages. The closure 20c is substantially identical to the closure 20b shown in Figures 9 and 10 and includes a thickened base wall 22c having an annular, peripheral inner surface 52c that slopes upward and outward toward a further peripheral portion. thin, of the base wall 22c that joins the # Arched annular wall 26c. The liner 30c is formed of a flat outer surface 32c, an inclined inner top surface 50c, complementary to the base surfaces 5 22c and a tapered annular surface 50c complementary to the tapered surface 52c. Those closures for carbonated drinks, as described above, must meet the testing requirements of custom, which include the torque required to remove it; retention of carbonation, leaks; maximum load; and air content. Referring to Figure 12, the Typical tools for compression molding the liner in a closure comprise a core 60, an intermediate sleeve 62 and an outer sleeve 64 that define the cavity into which the liner will be formed. In the method for forming the closures described above, the granules of plastic material are supplied to the interior of the closure and the tool moves towards the cavity. The sleeve 64 of the tool is attaches to the base wall of the seal to seal against the base wall of the closure and form a cavity around which the granules and the tip or inner core 60 and the sleeve 62 of the tool move axially to compress the granules on the liner 30. It has been found that the closure with Lining, resulting, can be manufactured at high speeds and eliminating splashes and empty spaces or hollow s. It can be seen that a plastic closure and method of making the plastic closure has been provided, wherein the plastic closure has a configuration such that the plastic closure will provide an effective seal in glass and plastic containers, at the same time that provides a positive cut; wherein a more uniform flow of liner material occurs during compression molding, whereby splashing and void or void formation are eliminated; which can be used as a vacuum closure for containers filled with hot contents; which can be used as a closure for containers filled with cold, non-carbonated liquids; and that can be used for containers that contain carbonated drinks. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (6)

1. CLAIMS 1. A plastic closure for a container having a neck with an upper surface portion, a cylindrical outer surface portion, at a predetermined outer diameter, a cylindrical inner surface portion, a certain predetermined inner diameter, a curved inner surface portion , at the junction of the inner cylindrical surface portion and the upper surface portion, and an outer curved portion at the junction of the upper surface portion and the outer surface portion, the closure is characterized in that it comprises: a wall of base, a skirt or side wall, peripheral, having an inner surface, means for mutual coupling placed on the inner surface of the skirt, to be coupled to the container, the base wall has an interior surface generally flat, a liner or compression molded liner on the inner surface of the plastic closure, the liner has a periphery spaced radially inwardly from the peripheral skirt and the means for mutual coupling that lie on the skirt, and has a smaller outside diameter than the outer diameter of the neck, the liner includes an outer surface inclined inwardly and towards the axis of the closure and axially withdrawn from the base wall, the inclined outer surface, which is on the liner, has an inner diameter smaller than the inner diameter of the neck, and is located to engage the upper surface portion of the neck and the curved, inner surface portion of the container neck and to exit engagement with the outer surface and the curved outer surface portion of the container neck .
2. 2. The plastic closure according to claim 1, characterized in that the base wall is thin enough Such a shape will flex inward due to the vacuum developed when the closure is applied to a container full of hot contents that are later allowed to cool.
3. 3. The plastic closure according to claim 1, characterized in that the base wall of the closure is sufficiently \ thick in such a way that it will not flex when 10 apply to a full container.
4. 4. The plastic closure according to the rei indication 1, characterized in that the mutual coupling means comprises threads, and the threads include axial grooves defining vent spaces such that the closure can be used in a container filled with carbonated beverages .
5. 5. The plastic closure according to claim 4, characterized in that the closure has a sufficiently thick base wall in such a way that it can not be expelled.
6. 6. The plastic closure in compliance # with claim 4, characterized in that the base wall of the closure includes an interior surface having an annular peripheral surface tapering from the flat surface, axially upwards and outwards. 1 . The plastic closure in compliance • v. W with claim 6, characterized in that the The liner has a top surface complementary to the flat surface and the tapered surface of the base wall. 8. The plastic closure in compliance 15 with any of the rei indications from 1 to 7, characterized in that the angle that the inclined surface of the liner forms with a plane at right angles to the axis of the closure, varies between one and fifteen degrees. 9. The plastic closure according to claim 8, characterized in that the angle that the inclined surface of the lining forms with a plane that is at an angle. straight with respect to the axis of the closure, varies between four and ten degrees. 10. The plastic closure according to claim 9, characterized in that the angle - that the inclined surface of the liner forms with a plane that is at right angles to the axis of the closure, is approximately four degrees. 11. A package characterized in that it comprises a closure according to any of claims 1 to 10, in combination with a container that 15 has a neck with an upper surface portion, a cylindrical outer surface portion, a predetermined outer diameter, an inner surface portion, cylindrical, inner diameter Preferably, a portion of curved, inner surface, at the junction of the cylindrical surface portion and the upper surface portion, and a curved, outer surface portion, at the junction of the portion of upper surface and outer cylindrical surface portion 12. A container, considered because 5 comprises: a plastic closure, a container having a neck with an upper surface portion, a cylindrical outer surface portion, a predetermined outer diameter 10, an inner, cylindrical surface portion, a predetermined inner diameter, a cylindrical inner surface portion at the junction of the inner cylindrical surface portion and the upper surface portion, and a curved portion at the junction of the upper surface portion and the outer cylindrical surface portion, the closure comprises a base wall, a skirt or side wall, peripheral, having an inner surface, means for mutual coupling placed on the inner surface of the skirt, to be attached to the neck of the container, # the base wall has a generally flat inner surface, a compression molded liner or liner on the inner surface of the plastic closure, the liner has a periphery spaced radially inwardly from the peripheral skirt and the means for mutual coupling which lie on the skirt, and has an outer diameter less than the outer diameter of the neck, the liner includes an outer surface inclined inwardly and towards the axis of the closure and axially withdrawn from the base wall, 15 the inclined outer surface , which is on the liner, has an inner diameter smaller than the inner diameter of the neck, and is located to engage the upper surface portion of the neck and the curved, inner surface portion of the neck of the container and to exit from the neck. coupling with the outer surface and the curved outer surface portion of the container neck. 25 13 The packaging in accordance with claim 12, characterized in that the base wall is sufficiently thin so that it will flex inward due to the vacuum developed when the closure is applied to a container filled with hot contents that are subsequently allowed to cool. 14. The confounding container with claim 12, characterized in that the wall * 10 base closure is thick enough so that it will not flex when applied to a full container. 15. The package according to claim 12, characterized in that the means for mutual coupling comprise threads, the threads include axial grooves defining spaces for venting so that the closure can be used in a container filled with carbonated drinks. 16. The container according to the rei indication 15, characterized in that the closure has a base wall which 25 sufficiently thick so that it does not will flex # 17. The package according to claim 16, characterized in that the base wall of the closure includes an interior surface having a peripheral, annular, tapered surface from the flat surface, axially upwards and outwards. * 18. The package according to claim 17, characterized in that the liner has a top surface complementary to the flat surface, and the tapered surface of the base wall. 19. The package according to any of claims 12 to 18, characterized in that the angle that the inclined surface of the liner, forms with a 20 plane that is at right angles to the axis of the closure, varies between one and fifteen degrees s. 20. The package according to claim 19, characterized in that the angle that the inclined surface of the liner, forms with a plane that is at right angles to the axis of the closure, varies between four and ten degrees. 21. The package according to claim 20, characterized in that the angle that the inclined surface of the liner, forms with a plane that is at right angles to the axis of the closure, is approximately four degrees. 22. A method for forming a plastic closure, for a container having a neck with an upper surface portion, a cylindrical outer surface portion, a predetermined outer diameter, an inner, cylindrical surface portion, to a predetermined inner diameter, an inner curved surface portion at the junction of the inner cylindrical surface portion and the upper surface portion, and a curved outer surface portion, at the junction of the upper surface portion and the outer surface portion, the closure comprises a base wall, skirt or side wall, peripheral, having an inner surface, means for mutual coupling placed on the inner surface of the skirt, for coupling to the neck of the container, the method is characterized in that it comprises the steps of: forming the base wall having a flat inner surface, * 10 supplying to the closure granules of molten plastic, and compression molding, a liner or coating, on the flat surface of the plastic closure, the step of compression molding. The lining is such that the lining is formed with a periphery spaced radially, inwardly of the peripheral skirt and of the mutual coupling means which are on the skirt and which have an outer diameter smaller than the outer diameter. 20 outer diameter of the neck, the liner includes an outer surface inclined inwardly and towards the axis of the closure, and axially removed from the base wall, the step of compression molding. 25 lining, includes forming the outer surface inclined to fit the portion of * upper surface of the neck and the curved, inner surface portion of the neck of the container, and so that it comes out of engagement with the outer surface portion and the curved, outer surface portion of the neck of the neck. 23. The method according to claim 10, wherein the step of forming the base wall is such that the base wall is sufficiently thin so that it will flex due to the vacuum developed when the closure is applied to a container. 15 filled with hot contents that are then allowed to cool. 24. The method according to claim 22, characterized in that the step 20 of forming the base wall of the closure, is such that the base wall is sufficiently thick, so that it will not flex when applied to a full container . < t 25. The method according to claim 27, characterized in that the step of forming the closure includes forming the mutual coupling means, such as threads with axial grooves defining vent spaces, such that the closure can be used in a container that is filled with carbonated drinks. * 26. The method according to claim 25, characterized in that the step of forming the closure is such that the base wall is thick enough so that it does not flex. 27. The method according to claim 26, sarasterized because the step * To form the base wall includes forming the inner surface in such a way that it has a 20 annular peripheral surface, which is housed from the flat surface, axially upwards and outwards. 28. The method according to claim 27, characterized in that the step % of forming the liner, is such that the liner has a top surface complementary to the flat surface and the tapered surface of the base wall. 29. The method according to any of claims 22 to 28, characterized in that the step of compression molding comprises forming the angle that the * 10 inclined surface lining form with a plane that is at right angles to the closure, so that it varies between one and fifteen degrees. 30. The method according to claim 29, characterized in that the angle of the inclined surface of the lining, * shape with a plane that is at right angles to the axis of the closure, varies between 20 four and ten degrees. 31. The method according to the rei indication 30, sarasterized because the angle that the inclined surface of the liner, 25 shape with a plane that is at an angle straight with respect to the axis of the closure, it is »Approximately four degrees. 32. The method according to any of claims 22 to 31, characterized in that the step of compression molding the liner on the base wall comprises providing tools that include 10 a sleeve for the liner, a tip for the liner, inside the sleeve, and an outer sleeve that surrounds the sleeve for the lining and that projects axially and beyond the sleeve, the sleeve of the liner, the tip for The liner and the outer sleeve cooperate to form a space with the bottom wall, of an inverted closure having the configuration of the liner, which includes a surface forming the inclined outer surface, of the liner, and after being supplied to the closure , the molten plastic granules, move the tools axially to cause the outer sleeve to engage the base wall of the closure, to form the load in that space. 25