CA1249241A - Closure with plastisol liner defining a retaining bead - Google Patents
Closure with plastisol liner defining a retaining beadInfo
- Publication number
- CA1249241A CA1249241A CA000447308A CA447308A CA1249241A CA 1249241 A CA1249241 A CA 1249241A CA 000447308 A CA000447308 A CA 000447308A CA 447308 A CA447308 A CA 447308A CA 1249241 A CA1249241 A CA 1249241A
- Authority
- CA
- Canada
- Prior art keywords
- liner
- plastisol
- skirt
- closure
- shell
- 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.)
- Expired
Links
Landscapes
- Closures For Containers (AREA)
Abstract
CLOSURE WITH PLASTISOL LINER
DEFINING A RETAINING BEAD
ABSTRACT OF THE DISCLOSURE
This relates to a closure utilizing a-liner which is formed of plastisol or like material which puffs or expands upon curing after the liner has been applied.
By providing the liner with a skirt portion and by in-creasing the radial thickness of a lower part of the liner skirt portion through a shaping of the skirt of the closure shell, the cured liner skirt portion will expand differentially and form, on the inner surface of the liner skirt portion, a bead which will snap over and lock beneath a bead on a container neck finish to lock the closure in a container sealing position. The closure may be removed and reapplied to reseal the container.
DEFINING A RETAINING BEAD
ABSTRACT OF THE DISCLOSURE
This relates to a closure utilizing a-liner which is formed of plastisol or like material which puffs or expands upon curing after the liner has been applied.
By providing the liner with a skirt portion and by in-creasing the radial thickness of a lower part of the liner skirt portion through a shaping of the skirt of the closure shell, the cured liner skirt portion will expand differentially and form, on the inner surface of the liner skirt portion, a bead which will snap over and lock beneath a bead on a container neck finish to lock the closure in a container sealing position. The closure may be removed and reapplied to reseal the container.
Description
CLOSURE WITH PLASTISOL LINE~
DEFINING ~ RETAINING BEAD
This invention relates in general to new and useful improvements in closures for containers wherein the closure is provided with a plastisol liner for form-ing a seal with the container neck finish, and more particularly to a modified closure wherein the plastisol liner has an integral bead for locking engagement on a container neck finish bead.
It is conventional to provide closure caps with a shell having disposed therein a plastisol liner for forming a seal with the end finish of a container. Such liners normally have pximarily only an annular sealing surface, although the liners may extend slightly down the skirt of the shell. The plastisol liners are applied in their uncured state and then are cured, at which time a certain degree of e~pansion takes place and this improves the sealing properties of the liner. However, in order that the liner may be applied at a high production rate, it is con-toured by means of a molding punch, and thus the internal surface of the skirt portion of the liner must be of a straight line configuration in cross section.
Otherwise, there would be a wiping action as the molding punch is removed.
In accordance with this invention, the skirt portion of the plastisol liner, in its cured state, has a lower portion in the form of a locking or retention bead which projects radially inwardly beyond a~ially ad~acent portions of the liner skirt portion. This bead, inte-grally formed on the liner skirt portion, is engageable
DEFINING ~ RETAINING BEAD
This invention relates in general to new and useful improvements in closures for containers wherein the closure is provided with a plastisol liner for form-ing a seal with the container neck finish, and more particularly to a modified closure wherein the plastisol liner has an integral bead for locking engagement on a container neck finish bead.
It is conventional to provide closure caps with a shell having disposed therein a plastisol liner for forming a seal with the end finish of a container. Such liners normally have pximarily only an annular sealing surface, although the liners may extend slightly down the skirt of the shell. The plastisol liners are applied in their uncured state and then are cured, at which time a certain degree of e~pansion takes place and this improves the sealing properties of the liner. However, in order that the liner may be applied at a high production rate, it is con-toured by means of a molding punch, and thus the internal surface of the skirt portion of the liner must be of a straight line configuration in cross section.
Otherwise, there would be a wiping action as the molding punch is removed.
In accordance with this invention, the skirt portion of the plastisol liner, in its cured state, has a lower portion in the form of a locking or retention bead which projects radially inwardly beyond a~ially ad~acent portions of the liner skirt portion. This bead, inte-grally formed on the liner skirt portion, is engageable
-2- ~9~1 beneath a bead on a container neck finish so as to retain the closure on the container against accidental removal, although it may be readily pried from the container.
A principal feature of this invention is the fact that the plastisol, when cured, expands or puffs.
This characteristic of the liner material is beneficially utilized by varying the thickness of the liner in the skirt portion thereof. By making a lower part of the liner skirt portion of a greater thickness than the axially adjacent part, when the skirt portion expands radially lnwardly upon curing, the thinner part expands to a certain degree while the thicker part expands to a much greater degree even when the percentage of puffing i`n the two parts is the same.
Thus, by configurating the shell to have the lower part of the liner skirt portion of a greater thickness, the liner skirt portion may be provided with an integral bead after curing while the uncured liner will have a straight line cross-sectional interior surface.
A further feature of the invention is the utili-zation of a plastisol for forming the liner wherein thepercentage of puffin~ increases, within limits, as the thickness of the plastisol increases.
With the above and other objects in view that will hereinafter appearl the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims, and the several views illustrated in the accompanying drawings.
IN THE DRAWINGS:
Figure 1 is a top perspective view of a container closed by a closure formed in accordance with this inven-tion.
Figure 2 is a transverse vertical sectional view taken generally along the line 2-2 of Figure 1, and shows the specific cross section of the shell of the closure and the liner and the interlocking relationship between the liner and the container neck f;nish bead in accordance with this invention.
~3~ 2~
Figure 3 is an enlarged sectlonal view taken through the closure shDwi`ng in solid lines the contour of the plastisol liner as applied, and in dotted lines the puffed plastisol liner after curing.
Figure 4 is an enlarged sectional ~iew similar to Figure 3, but having thereon a number of lines upon which test dimensions were taken of both the as applied and puffed plastisol.
Figure 5 is a graph showing puff percentage plotted against initial liner thickness.
Referring now to the drawings in detail, it will be seen that there is illustrated in Figure 1 a conven-tional container 10 which includes a body 12 terminatingat its upper end in a neck finish 14. The neck finish 14 carries a closure formed in accordance with this inven-tion and generally identified by the numeral 16.
- Referring now to Figure 2, it will be seen that the il~ustrated container 10 is formed of glass, although it may be formed of other materials, and the neck finish 14 includes a free end sealing surface 18. The neck finish 14 also incluaes an external locking bead 2D which is integrally formed on the outer surface of the neck finish 1~ and is axially spaced below the sealing surface 18.
In the normal formation of closures such as the closure 16, there is a contoured shell 22 which is pro-vided with a plastisol ]iner, generally identified by the numeral 2~. The shell 22 may be provided with a radially 3Q inwardly directed locking bead or other means for direct locking engagemen-t with the container neck fi]lish. Nor-mally, the liner 24 is of an extent only to assure sealing with the sealing surface 18.
The shell 22, for the most part, is of a conven-tional construction and includes an end panel 26 surroundedby an a~ially inwardly opening channel portion 28. ~he _4_ ~2~
shell 22 also includes a generally cylindrical skirt 30 which terminates in an integral inwardly directed curl 32.
Normally, the liner 24 is primarily restricted to the channel 2g and does not materially extend axially down the skirt.
In accordance with this invention, instead of the skirt 30 being cylindri`cal the full height thereof, the skirt 3~ has an upper cyli`ndrical portion 34 and a radially outwardly and downwardly flared lower portion 36. Further, the liner 24, in addition to including an annular seal forming portion 38, also includes a skirt portion 40. It is this skirt portion 40 to which the invention primarily relates.
Referring now to Figure 3, it will be seen that the liner 2~ is contoured by means of a molding punch 42 to the preselected contour with the plastisol which forms the liner being in its uncured state. secause the molding punch 42 must be withdrawable, it is obvious that it cannot have any liner forming projections or recesses in the peripheral surface thereof. Therefore, the as applied uncured plastisol liner 24 must ha~e, in the skirt portion thereof, an internal surface which, in cross section, is a straiyht line. This i`nternal surface is identified by the numeral 44 and prefera~ly has a slight slope thereto so as to facilitate the withdrawal of the molding punch 42~
It will be readily apparent that this slope must be radially outwardly and axially downwardly.
Considering first the assumption tha-t upon being hea-ted and cured the plastisol material of the liner 24 will expand or puff and -that the expansion will be of a uniform rate irrespective of thickness, it will be seen that the internal contour of the liner 24 will be modified from the uncured contour in accordance with variation in thickness of the liner. Thus, by radially outwardly en--larging the shell skirt 30 and thereby providing for anincreased thickness in the lower part of the liner skirt _5~ r~
portion 40, as at 46, lt will be apparent that when the liner material puffs upon being cured this increase in thickness of the liner material at 46 will result in a radially inwardly directed greater expansion of the lower part of the skirt portion as opposed to the radially inwardly directed expansion of an axially adjacent part of the lîner skirt portion. Thus, by properly contouring the skirt of the shell 16, the lower part of the cured plastisol liner skirt 40 can be expanded to define a radially inwardly lQ directed bead identified by the numeral 48.
Referring now to the graph of Figure 5, it has been found that with certain plastisols, particular plasti-cized polyvinyl chloride that contains additives such as pig-ments, lubricants, stabili~ers, and puffing agents, the percentages of which additives vary depending upon the closure type and package treatment.
The plastisols, upon curing, do not uniformly puff, but that there is an increase in the pu~f rate of such plastisols in accordance with an increase in thickness.
It will be seen that when the thickness varies between .010"
and .031", there is a marked increase in puff rate with an increase in thickness until the puff rate increase drops off in generally the same manner as it rises, approaching a puff percentage of 50% when the initial liner thickness is on the order of .050".
With particular reference to Figure 4, it will be seen that the actual thicknesses of the lower part of the liner skirt, both uncured and cured, was taken along a series of lines with the following results:
DI _ERENTIAL P~FF
POSITIONINITIAL THICKNESS FINAL THICKNESS (ACTUAL) A .013 .026 B .012 .024 C .013 .025 D .016 .030 E 020 .040 J~2~
F .025 .046 G Ø31 .052 H .Q36 .059 I .041 .064 J .041 .060 K .040 .058 L .042 .059 M .036 .060 N .029 .058 lQ O .021 O054 P .013 045 Q 007 .032 Inasmuch as the thickness oE the plastisol of the uncured liner 24 may fall within this increased puff rate for the particular plastisol, this can be advantage-ouely utilized to control the puffing in the applied area 46 of the liner to specifically define the bead with a contour which will interlock beneath the bead 20 of the container neck finish. It is to be understood that by 2 a controlling the radial outward enlargement of the skirt 30 of the shell, the contour of the bead 48 may be spe-cifically controlled.
The closure 16, as thus formed, may be applied to the container 10 by a pressing on of the closure and the bead 48 will engage over and beneath the bead 20 with a "snap" action. The bead 48, upon application of the closure to the containex neck finish, wedyes underneath the bead 20.
The closure, when..applied as set forth above, may be readily pried off or thumbed off, depending upon the contour of the bead 48. AEter removal of the closure, resealing is simply accomplished by applying the closure on top the neck finish and pressing down until an audible snap occurs.. When this occurs, the container has been re-sealed.
-7~ 3~
Although. only a preferred embodiment of the closure has been specifically illustrated and described herein, it ;.s to be unde.rstood that mi.nor variations may be made in the closure,. most particularly the contour of the skirt of the shell and the contour of the liner skirt portion, wi`thout depart;ng from the spirit and scope of the învention as defined by the appended claims.
A principal feature of this invention is the fact that the plastisol, when cured, expands or puffs.
This characteristic of the liner material is beneficially utilized by varying the thickness of the liner in the skirt portion thereof. By making a lower part of the liner skirt portion of a greater thickness than the axially adjacent part, when the skirt portion expands radially lnwardly upon curing, the thinner part expands to a certain degree while the thicker part expands to a much greater degree even when the percentage of puffing i`n the two parts is the same.
Thus, by configurating the shell to have the lower part of the liner skirt portion of a greater thickness, the liner skirt portion may be provided with an integral bead after curing while the uncured liner will have a straight line cross-sectional interior surface.
A further feature of the invention is the utili-zation of a plastisol for forming the liner wherein thepercentage of puffin~ increases, within limits, as the thickness of the plastisol increases.
With the above and other objects in view that will hereinafter appearl the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims, and the several views illustrated in the accompanying drawings.
IN THE DRAWINGS:
Figure 1 is a top perspective view of a container closed by a closure formed in accordance with this inven-tion.
Figure 2 is a transverse vertical sectional view taken generally along the line 2-2 of Figure 1, and shows the specific cross section of the shell of the closure and the liner and the interlocking relationship between the liner and the container neck f;nish bead in accordance with this invention.
~3~ 2~
Figure 3 is an enlarged sectlonal view taken through the closure shDwi`ng in solid lines the contour of the plastisol liner as applied, and in dotted lines the puffed plastisol liner after curing.
Figure 4 is an enlarged sectional ~iew similar to Figure 3, but having thereon a number of lines upon which test dimensions were taken of both the as applied and puffed plastisol.
Figure 5 is a graph showing puff percentage plotted against initial liner thickness.
Referring now to the drawings in detail, it will be seen that there is illustrated in Figure 1 a conven-tional container 10 which includes a body 12 terminatingat its upper end in a neck finish 14. The neck finish 14 carries a closure formed in accordance with this inven-tion and generally identified by the numeral 16.
- Referring now to Figure 2, it will be seen that the il~ustrated container 10 is formed of glass, although it may be formed of other materials, and the neck finish 14 includes a free end sealing surface 18. The neck finish 14 also incluaes an external locking bead 2D which is integrally formed on the outer surface of the neck finish 1~ and is axially spaced below the sealing surface 18.
In the normal formation of closures such as the closure 16, there is a contoured shell 22 which is pro-vided with a plastisol ]iner, generally identified by the numeral 2~. The shell 22 may be provided with a radially 3Q inwardly directed locking bead or other means for direct locking engagemen-t with the container neck fi]lish. Nor-mally, the liner 24 is of an extent only to assure sealing with the sealing surface 18.
The shell 22, for the most part, is of a conven-tional construction and includes an end panel 26 surroundedby an a~ially inwardly opening channel portion 28. ~he _4_ ~2~
shell 22 also includes a generally cylindrical skirt 30 which terminates in an integral inwardly directed curl 32.
Normally, the liner 24 is primarily restricted to the channel 2g and does not materially extend axially down the skirt.
In accordance with this invention, instead of the skirt 30 being cylindri`cal the full height thereof, the skirt 3~ has an upper cyli`ndrical portion 34 and a radially outwardly and downwardly flared lower portion 36. Further, the liner 24, in addition to including an annular seal forming portion 38, also includes a skirt portion 40. It is this skirt portion 40 to which the invention primarily relates.
Referring now to Figure 3, it will be seen that the liner 2~ is contoured by means of a molding punch 42 to the preselected contour with the plastisol which forms the liner being in its uncured state. secause the molding punch 42 must be withdrawable, it is obvious that it cannot have any liner forming projections or recesses in the peripheral surface thereof. Therefore, the as applied uncured plastisol liner 24 must ha~e, in the skirt portion thereof, an internal surface which, in cross section, is a straiyht line. This i`nternal surface is identified by the numeral 44 and prefera~ly has a slight slope thereto so as to facilitate the withdrawal of the molding punch 42~
It will be readily apparent that this slope must be radially outwardly and axially downwardly.
Considering first the assumption tha-t upon being hea-ted and cured the plastisol material of the liner 24 will expand or puff and -that the expansion will be of a uniform rate irrespective of thickness, it will be seen that the internal contour of the liner 24 will be modified from the uncured contour in accordance with variation in thickness of the liner. Thus, by radially outwardly en--larging the shell skirt 30 and thereby providing for anincreased thickness in the lower part of the liner skirt _5~ r~
portion 40, as at 46, lt will be apparent that when the liner material puffs upon being cured this increase in thickness of the liner material at 46 will result in a radially inwardly directed greater expansion of the lower part of the skirt portion as opposed to the radially inwardly directed expansion of an axially adjacent part of the lîner skirt portion. Thus, by properly contouring the skirt of the shell 16, the lower part of the cured plastisol liner skirt 40 can be expanded to define a radially inwardly lQ directed bead identified by the numeral 48.
Referring now to the graph of Figure 5, it has been found that with certain plastisols, particular plasti-cized polyvinyl chloride that contains additives such as pig-ments, lubricants, stabili~ers, and puffing agents, the percentages of which additives vary depending upon the closure type and package treatment.
The plastisols, upon curing, do not uniformly puff, but that there is an increase in the pu~f rate of such plastisols in accordance with an increase in thickness.
It will be seen that when the thickness varies between .010"
and .031", there is a marked increase in puff rate with an increase in thickness until the puff rate increase drops off in generally the same manner as it rises, approaching a puff percentage of 50% when the initial liner thickness is on the order of .050".
With particular reference to Figure 4, it will be seen that the actual thicknesses of the lower part of the liner skirt, both uncured and cured, was taken along a series of lines with the following results:
DI _ERENTIAL P~FF
POSITIONINITIAL THICKNESS FINAL THICKNESS (ACTUAL) A .013 .026 B .012 .024 C .013 .025 D .016 .030 E 020 .040 J~2~
F .025 .046 G Ø31 .052 H .Q36 .059 I .041 .064 J .041 .060 K .040 .058 L .042 .059 M .036 .060 N .029 .058 lQ O .021 O054 P .013 045 Q 007 .032 Inasmuch as the thickness oE the plastisol of the uncured liner 24 may fall within this increased puff rate for the particular plastisol, this can be advantage-ouely utilized to control the puffing in the applied area 46 of the liner to specifically define the bead with a contour which will interlock beneath the bead 20 of the container neck finish. It is to be understood that by 2 a controlling the radial outward enlargement of the skirt 30 of the shell, the contour of the bead 48 may be spe-cifically controlled.
The closure 16, as thus formed, may be applied to the container 10 by a pressing on of the closure and the bead 48 will engage over and beneath the bead 20 with a "snap" action. The bead 48, upon application of the closure to the containex neck finish, wedyes underneath the bead 20.
The closure, when..applied as set forth above, may be readily pried off or thumbed off, depending upon the contour of the bead 48. AEter removal of the closure, resealing is simply accomplished by applying the closure on top the neck finish and pressing down until an audible snap occurs.. When this occurs, the container has been re-sealed.
-7~ 3~
Although. only a preferred embodiment of the closure has been specifically illustrated and described herein, it ;.s to be unde.rstood that mi.nor variations may be made in the closure,. most particularly the contour of the skirt of the shell and the contour of the liner skirt portion, wi`thout depart;ng from the spirit and scope of the învention as defined by the appended claims.
Claims (11)
1. A closure comprising a shell having a cured plastisol liner wherein the plastisol is in a puffed state, said liner having a lower radially inwardly directed locking bead formed solely due to the puffed state of said plastisol for locking engagement beneath a container neck finish bead.
2. A closure according to claim 1 wherein said shell has a cylindrical upper portion and is radially outwardly enlarged in the area of said locking bead with the thickness of said liner at said locking bead being greater than the thickness of said liner in axially adjacent portions of said liner due to said puffed state.
3. A closure according to claim 2 wherein said liner terminates below said locking bead in a tapered ramp which terminates at said shell intermediate ends of said shell enlargement.
4. A closure according to claim 1 wherein said plastisol has a puff rate which increases with thickness.
5. An intermediate article of manufacture for forming a closure having a cured plastisol liner with said liner having a lower radially inwardly directed locking bead, said intermediate article of manufacture comprising a shell having in the interior thereof a liner of uncured plastisol, said liner including a skirt portion having an internal surface free of radially inwardly directed projections, and said shell adjacent a portion of said liner skirt being radially outwardly enlarged wherein the thickness of a lower portion of said liner skirt is greater than the thickness of an adjacent portion of said liner.
6. An intermediate article according to claim 5 wherein said plastisol is of the type which puffs when cured whereby thickened areas increase in thickness to greater linear extent than thinner areas.
7. An intermediate article according to claim 6 wherein said plastisol has a puff rate which increases with thickness.
8. A method of forming a closure of the type including a shell having a plastisol liner for sealing engagement with a container, said method comprising the steps of providing a shell having a skirt and wherein a lower portion of said skirt is radially outwardly enlarged, applying an uncured plastisol liner to the shell with the liner having a skirt portion extending axially into overlapped relation with the outwardly enlarged portion of the liner skirt, and then curing the liner effecting a puffing of the plastisol of the liner with the resultant grater radial expansion of the liner skirt portion of greater thickness defining on the liner skirt an intgral radially inwardly directed locking bead for locking engagement with a bead on a container neck finish.
9. The method of claim 8 wherein the skirt of the uncured liner has an interior surface which is a straight line in cross section.
10. The method of claim 8 wherein the uncured liner is contiured by means of a molding punch.
11. The method of claim 8 wherein the plastisol has a puff rate which increases with thickness.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000447308A CA1249241A (en) | 1984-02-13 | 1984-02-13 | Closure with plastisol liner defining a retaining bead |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000447308A CA1249241A (en) | 1984-02-13 | 1984-02-13 | Closure with plastisol liner defining a retaining bead |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1249241A true CA1249241A (en) | 1989-01-24 |
Family
ID=4127172
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000447308A Expired CA1249241A (en) | 1984-02-13 | 1984-02-13 | Closure with plastisol liner defining a retaining bead |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1249241A (en) |
-
1984
- 1984-02-13 CA CA000447308A patent/CA1249241A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |