EP1991084A2

EP1991084A2 - Dispensing containers

Info

Publication number: EP1991084A2
Application number: EP07734483A
Authority: EP
Inventors: Andreas Geiger
Original assignee: Obrist Closures Switzerland GmbH
Current assignee: Obrist Closures Switzerland GmbH
Priority date: 2006-02-25
Filing date: 2007-02-14
Publication date: 2008-11-19
Also published as: MX2008010872A; WO2007096776A3; WO2007096776A2; GB0603978D0; BRPI0707808A2

Abstract

A container (1) is provided and comprises: an inner receptacle (10) having required internal contours and/or dimensions; and an outer cover (11) formed over at least part of the receptacle so as to achieve required external contours and/or dimensions. A method of forming a container is also provided.

Description

DISPENSING CONTAINERS

This invention is concerned with improvements in or relating to containers and is particularly, although not exclusively, concerned with containers intended for use as dispensers of liquid toiletries such as deodorant compositions. Though hereinafter described by reference to deodorant dispensers, it is to be clearly understood that the present invention can be used for other purposes, as for example the dispensing of liquid form adhesive compositions.

Deodorant dispensers are available in different forms, the two most common of which are known generally as the 'spray-on' and the 'roller- ball' or 'roll-on' dispensers. Hereinafter, though the invention is described with reference to the roll-on type of deodorant dispenser, it is also to be clearly understood that the invention is equally applicable to other types of dispenser which have provision for storing liquid deodorant, such as spray-on dispensers.

Typically, deodorant dispensers of the roll-on type comprise a receptacle which is made from glass or from a suitable rigid, semi-rigid or partially flexible plastics material, the receptacle having a neck portion which is designed to hold a roller ball in a manner such that as the ball is rotated when brought into contact with the skin, deodorant liquid is dispensed on the surface of the ball. To this end the neck portion is formed to restrain the ball in position so that it does not become detached from the neck portion, while still permitting liquid deodorant to disperse over the surface of the ball for application to the skin. As mentioned, some roll-on containers have the receptacle for the deodorant liquid formed from glass and are referred to as bottles as a result. The wall thickness of the glass can be quite inhomogeneous and thick as a result; typically the thickness is about 3 to 5mm in order for the bottle to withstand normal usage.

In order to improve production and to increase cost effectiveness, it is advantageous to produce such containers in synthetic materials such as thermoplastic materials. Use of glass requires, for example, lubricants for the glass while hollow glass manufacturing is considered to be successful only when it is a continuous process. Furthermore, glass moulding machines for bottles demand lubricants with a wide temperature range and the ability to evaporate residue free. In addition, techniques for moulding glass do not permit of fine detail in the finished product such as may appeal to the purchaser of the finished article albeit that that article is simply a container for the desired product.

However, to replace the glass product by an equivalent container made from plastics material having a similar if not identical appearance as to size and shape requires consideration being given as to whether or not that container will have similar volume content, wall thickness and like factors all of which have an influence on other elements of a production line.

Replacing a glass receptacle with a single skin plastics bottle would lead to a dilemma. For a plastics container of the same shape and size as a glass counterpart, the same wall thicknesses will introduce problems regarding the cycle time in manufacture of the container, for example, because of high cooling times for thick section thermoplastic bodies. However, thinner walls will result in a different, i.e. larger, filling capacity, thus resulting in modifications being necessary to an entire production line simply due to change of the material of the container.

It may be therefore desirable to use thermoplastic materials rather than glass in many cases. In doing so it may be preferable to have a container with the same or similar internal and external dimensions. To produce a container from a thermoplastics material as a single body with the same dimensions as a glass bottle would be impractical because containers with the same wall thickness would be very expensive and involve very long cooling times.

The applicants have therefore developed with the present invention a novel approach to such container design which provides, in one aspect, a container comprising an inner receptacle having required internal contours and/or dimensions and an outer cover formed over at least part of the receptacle whereby to achieve required external contours and/or dimension.

The outer jacket may have internal contours and dimensions at least substantially matching external contours and dimensions of the inner receptacle. Thus the container comprises two parts, the inner one of which can be formed with wall thicknesses, for example in the range of lmm to 2.5mm and preferably 1.2mm, which are considerably less than the 3.5 mm thickness required of the equivalent glass container, while the thickness of the outer cover can be of similar thickness, for example in the range of lmm to 2.5mm and preferably 1.2mm, to provide equivalent strength and resilience to that of the glass container. This provides a significant saving of material on a production line while higher assembly costs associated with fitting of the cover to the receptacle are readily recovered due to much shorter cycle times for manufacture of the two parts.

The receptacle can provide the internal dimensions without needing a thick wall because the external dimensions are provided by the jacket.

As will be readily appreciated, by suitably shaping both the receptacle and its outer cover, it is possible to emulate the appearance and size of the equivalent glass container and to ensure that it has not only the same outside dimensions but also the same or a similar filling volume, thereby removing the need to modify other steps or stages in the production line. In addition, such a container as is provided by the present invention gains from the fact that, as is well known, it is possible to detail the external appearance of a container moulded from a plastics material more exactly than when glass is used. In a preferred embodiment of the present invention, the body portion may be formed with a recess which has practical as well as aesthetic use. The recess, while imparting uniqueness of appearance to the finished container, also provides a handgrip for the user of the container.

One form of such a recess is formed by the intersection of: (i) an arc shaped segment of the body portion which curves from diametrically opposite sides of the body adjacent a base region thereof at an incline to an axis of the body; and of (ii) a curved conic section which extends away from the base region and inwardly of a main surface of the body portion.

The body portion of a container according to the present invention may also include a neck portion adapted to receive a cap member which may be screw threaded or arranged to form snap fitting engagement with the neck portion. The neck portion may be arranged to receive a roller ball for movement to dispense fluid contents of the receptacle, which may be of generally cylindrical shape or any other desired shape. The neck portion may be provided by the receptacle and/or the cover.

By forming the container in two parts, namely the receptacle and the outer cover it is possible not only to provide the required physical properties to the container, such as resilience and rigidity, but also to design the outer cover so that it covers only predetermined parts of the receptacle by providing 'cut-out' portions through which the receptacle is exposed. In this way, it is possible to impart a two-colour appearance to the container. Exposure of the, inner, receptacle does of course result in thinner wall thickness in those regions but this can be compensated by appropriate contouring of the receptacle.

Using appropriate moulds, it is also possible to shape and taper the thicknesses of the two parts of the container so that the outer surface of the receptacle and that of the cover are contiguous, thereby avoiding unsightly or sharp edges.

Polyethylene terephthalate (PET) is a preferred plastics material for use in moulding the receptacle though other plastics materials may be used, especially other suitable thermoplastics materials, such as polypropylene or other polyesters

The outer cover is preferably also formed of a thermoplastics material such as a suitable polypropylene. Polypropylenes are especially suitable because they have physical characteristics, which allow them to be shrink-fitted onto the receptacle. As with the receptacle, the cover can be formed of a single colour plastics material or may be formed from multicolour material. Shrink fitting of the cover onto the receptacle could be achieved by employing either a heat shrinkable plastics material or a plastics material, which shrinks on cooling. From a production viewpoint, it is preferred to use the latter.

In one embodiment the container may comprise a thin- walled PET receptacle and a thin- walled injection moulded jacket. The cover can be formed with a closed base portion or may be open at each end. Where the cover is formed with a closed base portion, assembly of the cover onto the receptacle can, in the course of production, be either by locating the cover onto the receptacle or vice versa. Where the cover is open at each end, it can be fitted onto the receptacle by sliding it over the receptacle either from the top of the receptacle or the bottom and is preferably in a heated expanded state so that, when located on the receptacle, it can shrink as it cools.

The present invention also provides, in another aspect, a method of forming a container comprising an inner receptacle having required internal contours and/or dimensions and an outer cover formed over at least part of the receptacle whereby to achieve required external contours and/or dimensions, the method comprising the steps of:

(a) moulding a receptacle from a thermoplastics material to give the required internal contours and/or dimensions;

(b) moulding a cover from a thermoplastics material; and

(c) mounting the cover on the receptacle.

In a preferred method, the receptacle is moulded by an injection blow moulding process in which a small part with a large wall thickness (a so-called preform) is first produced by injection moulding. The preform is heated and then transferred to the blow-moulding machine where it is blown into final shape. Compared to blow moulding, injection blow moulding gives better definition of details (e.g. screw threads), and a better control of the distribution of the thickness of the material. Final assembly is carried out by assembling the heated covers, directly after the injection moulding process, with the "cold" receptacles. Shrinkage of the covers after cooling down to room temperature can be used to give a tight fit.

In a preferred embodiment an injection moulded cover is assembled onto a cold receptacle when it is still warm just after it is ejected from the mould at step b). When the cover is placed on the receptacle and allowed to cool it shrinks onto the outer surface to form an outer skin. If the receptacle and/or cover are provided with co-operating features, such as projections, this could be used to enhance the association of the parts further.

As previously stated, preferred materials for manufacture of a container according to the present invention are thermoplastics materials, which are recyclable, for example PET for the receptacle and a polypropylene for the cover.

There now follows a detailed description which is to be read with reference to the accompanying drawings of a container according to one embodiment of the present invention. It is to be clearly understood that this illustrated embodiment has been selected for description to illustrate the invention by way of example only and not by way of limitation. In the accompanying drawings :-

Figure 1 is a side view of a receptacle of a container according to a preferred embodiment of the present invention; Figure 2 is a side view of the receptacle shown in Figure 1 ;

Figure 3 is a front view of an outer cover for the receptacle shown in Figures 1 and 2;

Figure 4 is a side view of the cover shown in Figure 3;

Figure 5 is a perspective view of a container according to the present invention assembled from the receptacle of Figures 1 and 2 and the outer cover of Figures 3 and 4; and

Figure 6 is a perspective cut away view of the container shown in Figure 5.

Referring to Figures 1 to 4, they illustrate a container 1 which comprises a receptacle 10, that is intended for containing a liquid deodorant and is designed to be held in the hand, and a jacket, sleeve or cover 11. The receptacle is generally indicated at 10 and comprises a central body portion 12 integrally formed with a base portion 14 and a neck portion 15, the body portion being in the form of a recessed cylinder having a central axis A. As shown in Figures 1 and 4, the base portion is inset at 16 so that the receptacle sits on a peripheral rim 18 thereby imparting greater stability to the container when assembled as described below. The base portion 14 is of substantially uniform internal and external diameters providing a wall thickness of the order of 1.2 mm. The central body portion 12 has a unique shape. Extending upwardly from the base portion a recess 20 is formed in the otherwise cylindrical body portion. The recess 20 commences approximately one sixth up the height of the receptacle measured from its base line B. The recess is defined at its lowermost edge along a substantially semicircular line 22 which lies in a plane normal to the axis A of the body portion of the receptacle. Upwardly of the line 22, and within the confines of the recess 20, a curved wall portion 24 of the body portion 12 of generally curved conic section tapers upwardly and inwardly so that it has a constantly reducing curvature as shown especially in Figures 2 to 4.

Extending downwardly from a position approximately one quarter of the height of the receptacle 10 an inwardly curved arc-shaped segment is provided by an arcuate surface 26 which is defined between two parabolas D and E, an upper and outer one D of which defines the outer limit of the curved surface and of the recess 20, and the inner one E of which is formed by the intersection 25 of the curved surface 26 with the wall portion 24. The intersection 25 itself is formed as an arcuate concave surface, which curves between the parabola E and the parabolically shaped edge F of the wall portion 24. The surface 26 is inwardly curved in the sense that it curves into the body portion 12. Both of the parabolas D and E and the parabolically shaped edge of the wall portion 24 terminate at the extremities of the line 22. The recess 20 provides means whereby the container, when assembled, can be gripped securely in the hand. The body portion 12 of the receptacle 10 terminates at its upper extremity at a shoulder 28 where the integrally formed neck portion 15 is formed. The neck portion 15 provides a screw thread 30 for accommodating an internally threaded cap member (shown in dotted outline in Figure 1 only). The thread 30 is ideally designed so that its shape allows a cap member to be screwed onto the receptacle in a substantially airtight manner so that the contents of the receptacle are prevented from evaporating.

The receptacle is preferably formed, as previously described, by an injection blow moulding process.

The outer cover 11, which is designed to fit tightly onto the receptacle 10, is formed by an injection moulding process and is formed of a material such as a thermoplastics material, for example polypropylene, that will allow for sufficient shrinkage as it cools to permit the cover to clamp to the body portion and the base portion of the receptacle.

The outer cover 11 is shown in detail in Figures 3 and 4 and comprises an outer base portion 34 which is cylindrical and is of a height which is substantially the same as the height of the base portion 14 of the receptacle 20. The outer cover also has a body portion 35 which is integral with the base portion. Viewing Figures 3,4, 5 and 6, it can be seen that the base portion of the outer cover forms an apron 36 which, when the outer cover is assembled on the receptacle overlies the base portion 14 of the receptacle, around the front of the receptacle. Above the base portion of the outer cover, the body portion is cut away, as shown at 38 to provide an opening 40 which corresponds in shape to the perimeter of the recess 20 as defined by the curved parabola D and the baseline 22. Above the opening 40, the outer cover resumes the shape of a cylinder, defining an annular upper portion 42 so that the opening 40 is defined between the base portion 34 and the annular portion 42. The axial length of the outer cover is substantially the same as that of the body portion of the receptacle 10.

Edges of the outer cover 11 are preferably rounded and may be contoured so that, when the outer cover is positioned on the receptacle, there are no apparent sharp edges and the surfaces of the receptacle and of the outer cover are apparently continuous.

As shown in the Figures, the illustrated embodiment also has an inset portion 44 which has contours such that its internal contours and dimensions match those of the external contours and dimensions of the inset portion of the receptacle when the two are finally assembled.

As previously mentioned, the outer cover is formed by injection moulding and is formed from a material such as polypropylene to have internal dimensions and contours such that, when it is removed from the mould in which it is formed, it conforms to the external contours and dimensions of the inner receptacle, when the two are assembled together. Allowance for mould shrinkage must be made when designing a mould for a part that requires close dimensional tolerances. Mould shrinkage of thermoplastic materials is very complex because it is affected by many factors and for polypropylene, a major factor is cooling rate. Generally, higher shrinkage results from slower cooling rates, and thicker parts shrink more than thinner parts. It takes longer to remove heat from thicker parts and consequently, in manufacturing the outer cover, the thickness of the outer cover is maintained uniform throughout the outer cover. Other factors affecting part shrinkage are melt temperature (which affects cooling rate), packing of the part, and the addition of fillers to the thermoplastics material, i.e. polypropylene, such as colouring agents and fillers where used.

Mould shrinkage for polypropylene can vary from about 0.010 mm/mm (0.010 in./in.) to about 0.030 mm/mm (0.030 in./in.), depending on part thickness, formulation, and processing conditions and the desired final contouring and dimensions of the outer cover must therefore be closely controlled so that it can be assembled onto the receptacle.

The mould for the outer cover is therefore correctly oversized to permit the cover to shrink as it cools, ideally to room temperature, when it has been assembled with the receptacle. The outer cover may be formed as single unit in an appropriate mould. However, it is also possible that the cover can be formed in two parts by injection moulding, with the two parts subsequently being bonded together either before they are assembled on the receptacle or during the process of assembling of the receptacle with the outer cover.

Assembly of the cover, when formed prior to assembly with the receptacle, is achieved by placing the receptacle inside the cover, and thereafter controllably cooling the container so formed to permit the cover to shrink onto the receptacle. The cover and the receptacle are of course aligned so that the opening in the cover exactly matches the profile of the recess in the receptacle.

In an alternative embodiment of the invention, the cover 11 may be formed without its inset portion 44 so that the general profile of the cover is essentially cylindrical. In such a case, the container 1 may be assembled by inserting the receptacle into either end of the cover. To prevent slippage of the cover relative to the receptacle, the cover may then be provided with inwardly directed lip portions (not shown) at one or both ends to ensure that the cover registers correctly with the receptacle. Such lip portions may be continuous annular lip portions or may be formed to reside in recesses formed in the ends of the body portion of the receptacle.

As a container according to the present invention is constructed of two parts, it is possible to form each individual part in a different coloured plastics material from the other, while each part can itself be formed of a plastics material which is itself multicoloured. Consequently, the present invention makes provision for a range of products, such as deodorants, to be displayed with the same packaging but using different colour combinations.

The embodiments of the present invention have been described with reference to attachment of a roll-on ball as is used in a deodorant dispenser. It will be clear to the man skilled in the art that the present invention is equally useful by attachment of the appropriate dispensing head to the neck portion of the container for example to dispense liquid from the container in other ways as for example by use of a pressurised spray.

Claims

1. A container comprising: an inner receptacle having required internal contours and/or dimensions; and an outer cover formed over at least part of the receptacle whereby to achieve required external contours and/or dimension.

2. A container as claimed in Claim 1, in which internal contours and dimensions of the cover at least substantially match the external contours and dimensions of the receptacle.

3. A container according to Claim 1 or Claim 2, wherein the outer cover is of a shape such that it covers only predetermined parts of the receptacle.

4. A container according to Claim 3, wherein the outer surfaces of the receptacle and the cover are contiguous.

5. A container according to any of Claims 1 to 4, wherein the receptacle is formed from a thermoplastics material.

6. A container according to any preceding Claim, wherein the receptacle comprises a body portion and a neck portion and the body portion is formed with a recess.

7. A container according to Claim 6, wherein the recess is formed by the intersection of (i) an arc shaped segment of the body portion which curves from diametrically opposite sides of the body adjacent a base region thereof at an incline to an axis of the body, and of (ii) a curved conic section which extends away from the base region and inwardly of a main surface of the body portion.

8. A container according to Claim 6 or Claim 7, wherein the neck portion of the body is adapted to receive a cap member.

9. A container according to any of Claims 6 to 8, wherein the neck portion is arranged to receive a roller ball for movement to dispense fluid contents of the receptacle.

10. A container according to any preceding Claim, wherein the receptacle is of generally cylindrical shape.

11. A container according to any preceding Claim, wherein the outer cover is formed of a material comprising a thermoplastics material.

12. A container according to Claim 11, wherein the thermoplastics material is a heat shrinkable material.

13. A container according to Claim 11 or Claim 12, wherein the thermoplastics material is selected from materials which shrink on cooling.

14. A method of forming a container comprising an inner receptacle having required internal contours and/or dimensions and an outer cover formed over at least part of the receptacle whereby to achieve required external contours and/or dimensions, the method comprising the steps of (a) moulding a receptacle from a thermoplastics material to give the required internal contours and/or dimensions;

(b) moulding a cover from a thermoplastics material; and

(c) mounting the cover on the receptacle.

15. A method according to Claim 15, in which step c) is performed immediately after step b) such that the cover is still malleable.

16. A method according to Claim 15 or Claim 16, wherein the receptacle comprises a body portion and a neck portion.

17. A method according to any of Claims 15 to 17, wherein the receptacle is formed by injection moulding at step a).

18. A method according to any of Claims 15 to 17, wherein the receptacle is formed by injection blow moulding at step a).

19. A method according to any of Claims 15 to 19, wherein the cover is formed by injection moulding at step b).

20. A method according to any of Claims 15 to 20, wherein the receptacle and the cover are assembled at step c) by placing the cover over the receptacle.