SPECIFICATIONVirgin sealed inner closure cap and method for its productionThe present invention relates to a virgin sealed inner closure cap for a small container such as, for example, a cosmetic tube or bottle.
Some small bottles and especially those for containing cosmetic liquid material, are provided with an inner closure cap having a small hole therethrough which fits tightly to an open mouth in the neck of the bottle so as to limit the amount of the cosmetic liquid material discharged to a small one. Such an inner closure cap is fitted after the bottle is filled with the liquid material through the open mouth. The inner closure cap is then covered by an outer closure cap which is fitted to or engages an external thread at the neck of the bottle.
Recently, in order to give visual proof that none of the cosmetic liquid material in the bottle has been used after filling prior to delivery to a user, it has been proposed to provide a virgin seal structure in the inner closure cap of the bottle. One of the proposed virgin seal structures is to form a tear-off cover portion which is integrally molded with the inner closure cap. The tear-off cover portion is normally defined from the remainder of the inner closure cap by a circular thin wall portion or by a circular perforation line which is designed to be torn-off along the thin wall portion or the perforation line by pulling a projecting tongue integrally formed on the tear-off cover portion. However, it has been very difficult to form the circular thin wall portion or the circular perforation line in such a manner that the tear-off cover portion can be removed very easily.This is particularly the case when the inner closure cap is a small one as is required for, for example, a cosmetic bottle or tube.
Another proposal for a virgin seal structure is to form a hollow closure protrusion integral with the inner closure cap, which is adapted to be cut out by a knife or scissors. However, such a structure is not desirable because the protrusion cannot be cut out easily without the use of a knife or scissors. Also, the shape of the inner closure cap is somewhat limited due to the pressure of the hollow closed protrusion thereon.
Accordingly, an object of the present invention is to provide a virgin sealed inner closure cap for a small container in which a pour-out hole can be formed very easily without the use of a special tool.
An object of an embodiment of the present invention is to provide a virgin sealed inner closure cap especially suited for fitting to a small open mouth in the neck of a bottle such as a cosmetic bottle.
According to the present invention there isprovided a virgin sealed inner closure cap fora container adapted to be tightly fitted to anopen mouth in the neck of the container andto be covered by an outer closure cap engagable with the outer periphery of said neck, saidinner closure cap comprising a base cap member of a thermoplastic resin for fitting to saidopen mouth and having a pour-out holethrough a top end wall thereof, and a plugmember removably fitted to said pour-out holeand having a tongue thereon, wherein saidplug member is made of another thermoplastic resin, which has no chemical affinity for that of said base cap member, and is lightlyattached to said base cap member to coversaid pour-out hole by using pressure to forcesaid plug member against said base cap member while at least a portion of said plugmember is molten.
According to a further aspect of the presentinvention there is also provided a method ofmanufacturing a virgin sealed inner closurecap for a container adapted to be tightly fitted to an open mouth in the neck of the containerand to be covered by an outer closure capengagable with the outer periphery of saidneck, said inner closure cap comprising abase cap member of a thermoplastic resin forfitting to said open mouth in the neck of saidcontainer and having a pour-out hole througha top end wall thereof, the method comprisingattaching a removable plug member having aholding tongue thereon, to said base capmember to cover said pour-out hole by usingpressure to force said plug member againstsaid base cap member while at least a portionof said plug member is molten said plugmember of another thermoplastic resin, whichhas no chemical affinity for that of said basecap member.
Embodiments of the present invention willnow be described by way of example withreference to the accompanying drawings, inwhich:Figure 1 is a vertical sectional view showinga cosmetic bottle covered with virgin sealedinner closure cap according to an embodimentof the present invention,Figure 2 is a partially sectioned perspectiveview showing the inner closure cap of Fig. 1,Figure 3 is a perspective view showing theinner closure cap of Figs. 1 and 2, in which aplug member is shown removed from a base cap rnember, Figure 4 is a partially sectioned perspectiveview showing a virgin sealed inner closure capaccording to another embodiment of the present invention, andFigure 5 is a partially sectioned perspectiveview showing a virgin sealed inner closure capaccording to a further embodiment of thepresent invention.
The embodiment of the present inventionshown in Figs. 1 to 3 will now be described.
A cosmetic bottle 1 for containing a cosmetic liquid material has an externally threaded neck portion 2, the top end of which provides an open mouth 3 for the bottle. After filling the bottle 1 with the cosmetic liquid material, the open mouth 3 is covered with an inner closure cap 4 of the present invention. The inner closure cap 4 is covered with and enclosed by an outer closure cap 5 which has an internally threaded skirt portion 6 engagable with the externally threaded neck portion 2 of the bottle 1. The inner closure cap 4 is provided to limit the amount of the cosmetic liquid material discharged to small one when it is desired to pour out the liquid material. The inner closure cap 4 tightly engages the open mouth portion of the bottle 1 so as not to allow easy removal therefrom.For example, the inner closure cap 4 made of resilient plastics material has a radially inwardly projecting annular flange 7 at the lower open end thereof which engages by press-fit a radially outwardly projecting annular flange 8 at the top end of the bottle 1.
The inner closure cap 4 of this embodiment of the present invention comprises a base cap member 9 and a removable plug member 10.
The base cap member 9 has the annular flange 7 engagable with the upper end of the bottle 1 and also has a pour-out hole 11 at the central portion thereof. The pour-out hole 11 generally has an inverted frusto-conical shape and is closed by the plug member 10 which has a tongue 1 2 attached thereto. The base cap member 10 is formed from thermoplastic resin by injection molding. The plug member 10 is also formed from another type of thermoplastic resin by injection molding.
The thermoplastic resin of the base cap member 9 is selected to be of a material which does not have a chemical affinity for the other thermoplastic resin of the plug member 10.
This means that when one molten thermoplastic resin is brought into contact with the other molten thermoplastic resin, the two resins cannot become combined integrally with each other but can be separated from each other after solidification without requiring a substantial force to be applied. Preferably, polyethylene resin is used as the resin for forming the base cap member 9 or the plug member 10, and polypropylene resin or polystyrene resin is used for forming the other member. In a practical embodiment, the base cap member 9 is initially formed from polyethylene resin and then polypropylene resin is injected into the pour-out hole 11 of the base cap member 9 by injection molding.Although as stated above, the polyethylene and polypropylene resins have no chemical affinity for each other, as a result of the polypropylene resin being injected under substantial pressure, the plug member 10 formed adhers lightly to the base cap member 9 to completely close and seal the pour-out hole 11. The adhesion of the plug member 10 is firm enough to prevent any leakage of the liquid material in the bottle even when the bottle is shaken while being held upside down.When it is desired to use the cosmetic liquid in the bottle for the first time, the user can remove the plug member 10 quite easily by holding and pulling up the tongue 1 2 on the plug member 1 0. Since the plug member 10 is not welded to be integral with the base cap member 9, the inverted frusto-conical wall of the base cap member 9 defining the pour-out hole 11 is very clean and substantially no trace of welding remains on this wall.
Once the plug member 10 is removed from the base cap member, the pour-out hole 11 of the base cap member cannot be sealed again by the plug member 1 0. Accordingly, it can be ascertained visually whether or not the contents of the bottle are virgin by the presence or absence of the plug member 10 in the inner closure cap 4 and hence provides visual proof of any unauthorized opening of the bottle.
In the embodiment of the present invention shown in Fig. 4, another type of virgin sealed inner closure cap 4a is provided which comprises a plug member 1 0a which is different from that of the first embodiment. In this case, a tongue 1 2a is provided which projects upwardly from the centre of the plug member 1 Oa. It is very easy to mold such a plug member 1 0a by injection molding on to a pour-out hole 11 a in a base cap member 9a.
Other structures and features of the inner closure cap 4a of this embodiment are substantially the same as those described in connection with that embodiment shown in Figs.
1 to 3.
Fig. 5 shows a further embodiment of the present invention having yet another type of virgin sealed inner closure cap 4b in which a plug member 1 orb is a sheet of thermoplastic resin. The disc-shaped plug member lOb which has a tongue 1 2b thereon is pressed against the periphery of a pour-out hole 11 b in a base cap member 9b under the action of heat until the disc-shaped plug member 10b is partially molten. Under the pressure, the molten part of the disc-shaped plug member lightly adhers to the periphery of the pour-out hole 11 b so as to close this hole. In this embodiment, an annular projection is provided at the centre of the base cap member 9b at the periphery of the pour-out hole 11 b, so that the pressing of the disc-shaped plug member 1 Ob against the periphery of the pour-out hole can be performed very easily.
As in the case of the previous embodiment, the base cap member 9b is made of polyethylene resin and the disc-shaped plug member 1 Ob is made of polypropylene resin or polystyrene resin.
As should be clear from the preceding descriptions of embodiments of the present in vention, the plug member 10 is formed from one thermoplastic resin having no chemical affinity for the thermoplastic resin from which the base cap member 9 is made and is lightly adhered to the base cap member 9 by the application of pressure with the use of heat.
Accordingly, although the sealing of the plug member is sufficient to prevent any leakage of the liquid material in the container, the plug member can be removed quite easily as desired from the base cap member by a very small pulling force. The attaching or adhering of the plug member to the pour-out hole of the base cap member can be carried out very easily when the molten thermoplastic resin of the plug member is injected to the pour-out hole of a base cap member previously formed.