GB2246317A

GB2246317A - Container

Info

Publication number: GB2246317A
Application number: GB9115644A
Authority: GB
Inventors: John Jeremy Wood
Original assignee: BXL Plastics Ltd
Current assignee: BXL Plastics Ltd
Priority date: 1990-07-24
Filing date: 1991-07-19
Publication date: 1992-01-29
Also published as: GB9115644D0; GB9016190D0; IE912584A1

Abstract

This invention relates to a method of injection blow moulding of a dispensing container from a plastics material. A pre-form (see fig 1) of the container is injection moulded to define a dispensing opening and the pre-form is subsequently inflated and blown to establish the container body shape. The closure for the opening is injection moulded integrally hinged to the container pre-form such that, in use, the closure is secured through threaded contour means to permit push-on application for closure and screw-off removal of the closure. Such a closure provides tamper evidencing and security features to the closed container. <IMAGE>

Description

Container This invention relates to a method for manufacturing a dispensing container and to a dispensing container so produced.

It has long been known to produce dispensing containers by injection moulding the container body and an integrally moulded closure hinged thereto in a single operation. The containers so produced are open at the bottom to permit filling after which they are closed by a separately produced plug.

It has also been proposed to injection mould a dispensing closure with integrally hinged closure plug on to a pre-formed tube for the production of a like container fillable via the open bottom to be subsequently closed and sealed by pinch-welding.

Further, it is well-known to injection-blow mould containers by a method wherein a container pre-form is first injection moulded in a pre-form mould cavity and then transferred to a blow-mould where it is inflated and blown to its final shape. In such a method it is well-known to configure the pre-form mould cavity whereby the neck of the container is provided with one or more moulded features to be retained in the final container, such as a thread and/or annular bead to facilitate the application of a container closure.

The commercial process of filling containers and subsequently closing them is complex and requires a complex combination of operations and apparatus and there is a need to simplify this for the user of containers where this is possible.

It is further desirable to produce containers and closures therefor efficiently and economically. The bottom filling of containers with subsequent sealing clearly contribute to the above-mentioned complex combination of operations while to produce a dispensing container with an integrally hinged closure not only simplifies the assembly of the completed container but reduces the moulding operations in container and closure production.

According to the present invention there is provided a method for the injection blow-moulding of a dispensing container from a plastics material wherein a pre-form of a container is injection moulded such as to define a dispensing opening and wherein said pre-form is subsequently inflated and blown to establish the container body shape, characterised in that a closure for said opening is injection moulded integrally hinged to said container pre-form such that, in use, the closure is secured through threaded contour means to permit push-on application for closure but only a screw-off removal of the closure.

Also provided according to this invention is a container produced by said method.

The process of injection blow-moulding of plastics bottles and other dispensing containers and its associated apparatus is well known and no detailed description is considered necessary here.

However, as indicated above, the two major stages in the process are the injection moulding of a pre-form in a pre-form cavity and then blowing the pre-form to the contours of a bottle mould with the material injected and blown being at suitable temperatures respectively. The temperature of injection may differ from the temperature of blow-moulding and such temperatures will depend on the plastics material employed.

Thermoplastics employed in the method of the present invention may be any thermoplastics material which can be injection moulded and extended in a blowing operation. Such a material may be selected from, for example, plasticised and unplasticised vinyl chloride polymers, high-, medium- and low- (including linear low-) density ethylene polymers, propylene polymers and polyethylene terephthalate and the like; the term polymers including homopolymers and copolymers generally. Combinations of polymers in admixture or otherwise may be employed with due consideration being given to compatibility factors.

When containers of this invention are produced with an integral hinge which is of the so called living hinge type rather than a mere strap hinge, and/or where repeated stressing across a hinge line occurs, the durability of the hinge can be usefully enhanced by selecting an orientable plastics material at least for the hinge.

Such orientation may be achieved during moulding of the hinge or it may be effected at least in part on first operation of the hinge.

However, where the hinge and the remainder of the container are of the same material a compromise is sometimes necessary in order to gain a satisfactory combination of properties.

In this respect high density ethylene polymers have been found to be a class of materials to be preferred for use in the manufacture of containers according to this invention and destined to contain household chemicals and detergents for example.

Materials having differing properties and/or colours may be used however for different parts of the container. For example, the injection moulding of the pre-form and closure may be via say two injection orifices each supplied with a material which differs from the other in properties and/or colour. A white pre-form of a container of high density polyethylene for example may be produced with a green integrally hinged closure of a different or same high density polyethylene. However, it is preferred that the container pre-form with integrally hinged closure is injection moulded using a single thermoplastics material and a single injection orifice.

The integrally hinged closure may be a single part closure or a multiple part closure. While the dispensing opening of the container may be moulded to provide a pouring spout or lip it may be required to moderate the dispensing via the closure. A multiple part closure therefore may be a dispensing closure with an over cap in turn integrally hinged to said dispensing closure for example.

As indicated above the integrally moulded hinge or hinges employed may include, for example, a simple line hinge type or a simple strap type or a sprung hinge type such as described in our copending British Patent Application 8924115.2 for example or, in the case of multiple hinges, a combination of such hinge types, as desired.

When a hinge is for example of the strap type, this may have a secondary function in providing a tamper evidencing feature. For example, the closure or over-cap, in use, being secured to the container opening or dispensing closure through threaded contour means, contoured in known fashion to permit together with the resilience of the material of the moulding a push-on application for closure but only a screw off removal of the closure, within reasonable operation, removal by such screwing off would only be permitted by severing the strap hinge. The threaded contour means used to provide a push-on screw-off closure system may be a profiled single-start or multi-start type. Such a profile may be employed on the inner surface of the closure with one or more matching and cooperating thread, cam or stud on the outer surface of the neck of the container.Alternatively, a thread or similar but inverted form may be incorporated on the inner surface of the closure to cooperate with a thread, cam or stud on the outer surface of the neck of the container as illustrated in Figure 6 below. Other tamper evidencing or security features could alternatively or additionally be incorporated in the closure of the container as will be evident to the skilled addressee. For example, a strippable band feature of known type could be incorporated.

The following description given with reference to the attached drawings is for the purpose of illustrating but to in no way limit the scope of the present invention: Figure 1 illustrates in side elevation a pre-form of a container produced in accordance with one embodiment of this invention and injection moulded with closure integrally hinged thereto.

Figure 2 illustrates in side elevation a container with closure integrally hinged thereto produced by inflating and blowing the pre-form shown in Figure 1.

Figure 3 illustrates the container with closure integrally hinged thereto of Figure 2 as seen from the rear.

Figure 4 illustrates in side elevation an alternative pre-form with closure to that shown in Figure 1.

Figure 5 illustrates in side elevation a container with closure integrally hinged thereto produced by inflating and blowing the pre-form shown in Figure 4.

Figure 6 illustrates in side elevation single-start and multi-start thread contours provided on the outer surface of the neck of the container and also a section of the thread profile.

In the drawings, like numerals refer to like components throughout.

Figure 1 shows an injection moulded thermoplastics container pre-form 1 produced on a core pin within a female mould, in known manner but with the mould in the region of the container dispensing opening extended to cause the injected material to flow and form integral hinge 3 and container closure 4. The thermoplastics material may be high density polyethylene.

The injection mould configuration provides the dispensing opening with pouring lip 5 and undercut surface 6 under which an annular bead (not shown) within closure 4 will snap to retain the closure in closed position in use.

The pre-form shown in Figure 1 suitably conditioned if necessary after moulding to stabilise its form and optimise physical properties of the material is transferred while supported on the core pin (not shown) within container body pre-form 7 and other male mould components (not shown) to a blow mould (not shown) to which the internal shape of the container body pre-form 7 is inflated and blown to conform.

The completed container of the general shape 8 shown in Figure 2 with integrally hinged closure is then cooled to stabilise its shape, removed from the blow mould and then stripped from the core pin and other male mould components using a combination of mechanical and pneumatic means in known manner.

The dispensing opening 2 as shown is of sufficient size to permit top filling of the container. Closure of the container is effected by rotating closure 4 as shown in figure 2 anti-clockwise about hinge 3 formed as a thin film line hinge to a point where the annular bead within closure 4 snaps under undercut 6 in known manner.

Figure 4 is similar to Figure 1 but shows an injection moulded thermoplastics pre-form 9 similarly produced but with a simpler shape of dispensing opening 10 and alternative strap type hinge 11 and modified closure 12.

Figure 5 shows the form 15 of container produced from the pre-form shown in Figure 4 in a manner generally analagous to that described with reference to Figures 1 and 2 particularly.

Closure of the container of Figure 5 is effected by rotating the closure 12 as shown, anti-clockwise whereby strap hinge 11 is -bent into a substantially U-shaped loop in known manner permitting an annular rib or bead moulded internally of closure 12 to snap under annular recessed surface 13.

Having now described the invention, variations and modifications to the specific embodiments will be evident to the skilled addressee and will not depart from the spirit of the invention.

Claims

Claims:

1. A method for the injection blow moulding of a dispensing container from a plastics material wherein å pre-form of a container is injection moulded such as to define a dispensing opening and wherein said pre-form is subsequently inflated and blown to establish the container body shape, characterised in that a closure for said opening is injection moulded integrally hinged to said container pre-form such that, in use, the closure is secured through threaded contour means to permit push-on application for closure but only a screw-off removal of the closure.

2. A method according to Claim 1 wherein the integrally hinged closure is moulded from material which is the same as that from which the container pre-form is moulded.

3. A method according to either Claim 1 or Claim 2 wherein the closure is a multiple part closure.

4. A method according to any one of the preceding Claims wherein the threaded contour means comprises one or more single-start or multi-start threads, cams or studs on the inner surface of the closure with matching and cooperating thread, cam or stud on the outer surface of the neck of the container.

5. A method as claimed in any one of the previous claims wherein the closure includes an additional strippable security band.

6. A dispensing container produced by the method of any one of the previous claims.