CA1183496A - Collapsible dispensing container having improved barrier insert in the container headpiece - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A collapsible dispensing container having a thermo-plastic headpiece united to a preformed tubular body wherein an improved barrier insert is fixed to the interior surface of the headpiece. The insert is preferably constituted of polybutylene terephthalate to prevent oxygen absorption and product permeation through the headpiece.

Description

This invention relates generally to collapsible dis-pensing containers used for packaging pharmaceutical produc-ts, dentifrice, cosmetics, toiletries and the like, and is particular-ly related to an improved plastic barrier insert in the head-piece of the container.
Collapsible dispensing containers are widely used for packaging various pharmaceutical products, dentifrice ~e.g., tooth pastes), medicinal ointments, and the like. The early containers were usually made of metal or plastic but more recent-ly such containers have been of laminated wall construction in which the container body is made of a multi-ply plastic laminate which includes an intermediate layer of a metal foil, notably aluminum foil, sandwiched between two thermoplastic layers. The metal foil layer serves as a barrier against oxygen permeating into the package and against the volatile ingredients of the packaged product permeating out and hence it is capable of pro-tecting the product from deterioration. Dispensing containers of laminate wall construction are described, for example, in United States patent No. 3,260,410 issued to Roger Brandt and Ralph Kaercher on July 12, 1966 and in United States Patent No.
3,347,419 issued to Roger Brandt and Michael Mestenas on October 17, 1967.

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- 2 -~ ~ ~3~96 While the provision of a metal foil b~rrier layer in the body o~ the container prevents product permeation and oxygen absorption in the body region o~ the container, it is essential that product permeation and oxygen absorption be prevented in all regions of the container, i.e., in the breast portion æs well. Thus, in United States Patent No. 3,260,777 which issued to Roger Brandt on July 12, 1966, in addition to providing a metallic barrier layer in the tube body, Brandt provides a barrier insert in the b~reast portion o~ the container. This metallic barrier member is constituted o~ a metal (e.g~, aluminum) ~oil and may be embedded in the breast portion o~ the tube during molding. However, the more desirable curren-t con-struction contemplates the use o~ a laminate insert wherein the metallic ~oil interlayer is between two thermoplastic layers.
A similar barrier insert is disclosed by Roger Brandt in United States Patent No. 3,295,725 which issued on January 3, 1967.
The disclosures oi both o~ the ai'orementioned patents o~ Roger Brandt are also ~u~ly incorporated herei~ by re~erence.
United States Patent No. 3,260,411 lssued to Frank Dobson on July 12, 1966 also discloses the use o~ barriers in bokh the body and headplece oi collapslbl0 dispensing containers ko prevent product permeation and oxygen absorption :in all re~ion~ o~ the container.
United States Patent No. 3,565,293 issued to Robert Schultæ on Pebruary 23, 1971 discloses a barrier layer o~ low permeability constituted o~ urea ~ormaldehyde thermosetting resin secured to the inside sur~ace o~ the headpiece.

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~834~6 The inserts disclosed in the aforementioned patents have not been entirely satisfactory. Metallic inserts and laminates having a metallic interlayer are difficu~t to fabricate and install in the headpiece. In addition, they are more expen-sive than plastic inserts. On the other hand, urea formaldehyde inserts tend to swell in the presence of products containing water, such as toothpastes and some pharmaceutical products.
This swelling can crack the breast portion of the tube head, re-sulting in product leakage through the breast area of the tube and is obviously unsatisfactory for the package. In addition, urea formaldehyde inserts are extremely brittle and, therefore, the inserts can crack during the use of the package.
Accordingly, the present invention provides a collaps-ible dispensing container of laminated wall construction wherein a plastic insert is provided at the breast of the container which will not only provide low essential oil and oY~ygen permea^
tion in all regions of the container, but will also prevent package failure.
The present invention also provides a thermoplastic insert in the headpiece of the container wherein the thermoplastic headpiece is resistant to swelling in the presence of water and is an effective barrier to essential oils and oxygen.
The present invention further provides such inserts which do not distort during the injection molding of the tube heacl to the tube body.
The present invention still Purther provides a plastic insert constituted from a thermoplastic material which can be fabricated and installed within the headpiece rapidly for more efficient and economical production of the container.
According to the present invention a collaps1ble dispensing container is provided having a deformable bocly and a t,hermopl~stlc headpiece unitecl thereto, ancl an improved barrier ~3~
member is secured to the interior surface of the headpiece.
The barrier member is preferably constituted of polybutylene ~erephthalate since thjs material is a barrier t~ essential oils, d~es n~t swell in the presense ~ water a~d ~e~t;frice products, has a relatiYely shDrt injec~i~n ~olding cycle and ~an be injected o~er with m~lten polyethylene ~ring the ~ssembly of the headpiece and the tube body, without distortion.
The barrier insert may also be constituted of injection moldable grade of polyethylene terephthalate or a b1end of ~ polybutylene terephthalate and injection moldable grade of polyethylene terephthalate.
The present invention will be further illustrated by way of the accompanying drawings, wherein like reFerence numerals, are employed to designate like parts and where;
Figure 1 is a fragmentary side elevational view, partly in section, of a collapsible dispensing container embodying the insert of the present invention;
Figure 2 is an enlarged fragmentary sectional view of the upper right hand portion of Figure l;
Figure 3 is a side elevational view of the barrier insert, and Figure 4 is a top view of the barrier insert.
Referring to the drawings, and first to Figure 1, there is shown a collapsible dispensing container designated ~neraliy as 11 having d tubular body 13 which is closed at its bottom end 15 and is united at its upper end to a headpiece 19 having a generally cone-shaped barrier member 27 which will also be hereinafter re~erred to as the insert.

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The container body 11 may be of a laminated wall con-struction capable of protecting the contents of the tube against oxygen attack and product permeation. Such laminated wall con-structions for tube bodies are described in several patents, including the aforementioned patents. Typically, and with reference to Figure 2, the laminated wall of the tube body com-prises an exterior layer 23, an intermediate layer 25 and an interior layer 27, all as hereinafter defined.
The exterior layer 23 is a suitable thermoplastic material such as polyethylene. This layer may also be constituted of a composite of two or more layers such as, for example, a layer of clear polyethylene over a layer of printed paper or over a layer of printed polyethylene for decorative purposes.
The intermediate layer 25 is a metallic barrier layer, usually an aluminum foil, which serves as a barrier layer to protect the product in the container tube against oxygen attack or product permeation.

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The inner l~yer 27 is also constituted of a thermo-plastic material which is compatible with the contents o~ the tube and which is capable o~ uniting to the headpiece when the headpiece ls thermally joined to the tube body. Thus, the layer 27 may be polyethylene or a composite o~ two or more layers, such as, for example, an interior polyethylene layer and an adhesive layer for adhésively joining the interior layer to the intermediate metal ~oi]. layer.
The headpiece 19 is usually a readily moldable thermo-plastic layer such as, -Por example, polyethylene and includes a neck portion 29 which is conveniently threaded ~or engagement with an internally threaded cap (not shown) to provide a closure ~or the con-tainer, The headpiece 19 also includes a breast portion 31 which is united, usually thermally, about its peripheral band or area 33 to the upper interior oi' the tube hody 11. The breast portion 31 has an annular lip 36 which underlies the insert 21 as shown in FIGURE 2.
In order to protect against oxygen attack and prevent product permeation in all regions o~ the container, the present invention provides a novel insert member 21 associated with the headpiece 19 as hereina~ter described in more detail. The selection o~ a suitable barrier insert in accordance with the present invention is based on several considerations which not only Lnclude protection against oxygen attack and product migration, but also involves consideration o~ manu~acturing procedure and di~iculties which, in the past, have been encountered with prior type barrier inserts.

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Thus, in accordance with this invention, i-t has been found that insert members made of polybutylene terephthalate (PBT) are particularly well suited for achieving a combination of desirable objeetives in the manufacture of collapsible dispensing containers. Among other advantages, the insert used herein is made entirely of plastic and does not contain a metallic layer as in the laminated inserts of the type used in the prior art. Consequently, they can be fabricated more readilty and at less cost.
In the a~orementioned United States Patent No 3,665,293 ol' 5chultz, the patentee discloses the use of an insert made ol' various resins selected on the bases of their impermeability and product compatibility. These resins include arnino resins, such as urea l'ormaldehyde, polypropylene and polyamides, such as nylon. In general, Schultz recommends using other plastic materials, both thermosetting and thermoplastic, which have the desired degree o~ impermeability and product compatibility. In addition, the patentee discloses that the insert may be made oi metal, such as, i'or example aluminum.
In a more recent patent, i.e., United States Paten~
No. 4,132,331 issued to Karl Magerle on January 2, 1979, the tube body consists oi' three layers; an outside layer oi poly-ethylene, a barrier sheet oi polyester and an inside layer which i~, al~o made o~ polye~hylene. The polyester barrier sheet ~or the tube body in Magerle is polyethylene terephthalate. The headpiece, however, does not have a polyester insert associated therewith.

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11~3~fi It has been discovered that a barrier insert made of polybutylene terephthalate does not swell in the presence o~
water found in various dentifrices, e.g., toothp~stes, or medicinal and pharmaceutical products, e.g., shaving creams, and the like. Also, this material is crystalline ~nd has a relatively short injection molding cycle. Since it can be molded more quickly, it can be made at less cost and better quality even though the cost of the resin is higher. In addition, unlike other thermoplastics, molten polyethylene used to ~orm the tube head can be injected directly on top o~ the PBT insert without distorting it. As it may be appreciated, freedom ~rom distortion during injection molding is highly signiiicarlt in the manufacture o~ the collapsible container.
In addition to the a~orementioned properties, an insert made o~ polybutylene terephthalate provides a barrier to essential oils and the ingredients which are usually present in denti~rice and pharmaceutical products, as ~ell as providing a barrier to oxygen which tends to permeate the product ~rom outside o~ the package.
As shown in FIGURES 3-4 the PBT insert 21 has a conical portion 35 which is designed to con~orm to the interior con~iguration o:~ -the breast portion 31 o~ headpiece 19. The conical portion 35 ~its tightly into the headpiece as at 37.
In practice, the ba~rier insert 21 is placed in positio n on the working tool and the tube head 19 is injected thereover.
The injection o~ the tube head 19 serves the dual purpose oi bonding the head to the sleeve portion to make a completed package, and i-t also locks the harrier insert securely in ~3~96 position through the annular lip 36. Alternatively, the insert 21 may be snapped into the interior surface of a pre-molded head having stop type locking ring for this purpose. In general, however, the manner in which the insert is associated with the headpiece is not, per se, a critical feature of the present invention, the same being known from prior patents, including the aforementioned patent of Schult7.
While the inserts of choice are made of polybutylene terephthalate, inserts made of injection moldable grade of polyethylene terephthalate or a blend of polybutylene terephtha-late with injection moldable grade of polyethylene terephthalate exhibit similar properties and hence they may be satisfactorily used in the practice of this invention.

Claims (8)

The embodiments of the invention in which an exclusive property or privilage is claimed are defined as follows:

1. A collapsible dispensing container comprising a de-formable body, a thermoplastic headpiece united with said body, and a barrier member secured to the interior surface of said headpiece, wherein said barrier member is made of polyethlene terephthalate, an injection moldable grade of polyethylene tere-phthalate or a mixture of polybutylene terephthalate and an in-jection moldable grade of polyethylene terephthalate.

2. A collapsible dispensing container as in claim 1 wherein said barrier member is made of polybutylene terephthalate

3. A collapsible dispensing container as in claim 1 wherein said barrier member is made,of injection moldable grade of polyethylene terephthalate.

4. A collapsible dispensing container comprising a de-formable body having low permeability, a thermoplastic headpiece including a peripheral band portion united to one end of said body, a barrier member conformally secured to the interior surface of said headpiece and having a peripheral edge disposed within and spaced from the inner wall of said body, said head-piece including an annular lip underlying and retaining said peripheral edge of said barrier member, wherein said barrier member is constituted of polybutylene terephthalate, an in-jection moldable grads of polyethylene terephthalate or a mix-ture of polybutylene terephthalate and an injection moldable grade of polyethylene terephthalate.

5. A collapsible dispensing container as in claim 4 wherein said barrier member is constituted of polybutylene terephthalate.

6. A collapsible dispensing container as in claim 4 wherein said barrier member is constituted of an injection moldable grade of polyethylene terephthalate.

7. A collapsible dispensing container as in claims 1, 2 or 3 wherein said barrier member includes a neck portion extending through the neck of said headpiece.

8. A collapsible dispensing container as in claims 4, 5 or 6 wherein said barrier member includes a neck portion extending through the neck of said headpiece.