A CONTAINER ASSEMBLY

Abstract: A container assembly and a method of constructing such an assembly has an outer container (1) a side wall (3) of which forms an open top, and has a blow moulded inner container (7) which forms a liner to the container (1). The liner (7) has a neck (8) which is secured to an internal flange (4) extending from the outer container. The flange (4) may be moulded integral with either the liner (7) or the outer container (1). A lid (10) has and external annular recess (12) which snap engages with an annular rib (5) on the flange (4) to form a sealed chamber in the assembly. The lid (10) and liner (7) are formed of the same first plastics material (for example PET) while the outer container (1) is formed of a different second plastics material (for example, polypropylene) so that the sealed chamber is defined wholly by the first plastics material which may be expensive but resistance to corrosion from contents (such as paint) stored in the chamber while the second plastics of the outer container may be inexpensive but non-resistant to corrosion from the contents in the chamber.

Description: TECHNICAL FIELD & BACKGROUND ART The present invention relates to a container assembly constructed of plastics materials and primarily intended for containment of liquids such as paint or solvents. Conventionally liquids such as paints and solvents are stored in metal cans or glass bottles, these however are expensive to form, heavy and in the case of glass bottles, fragile. There is therefore a demand for a lightweight, inexpensive and robust container formed from plastics materials and which is suitable for paints and solvents. However, many plastics materials which are inexpensive and shock resistant, such as polypropylene, and from which a suitable container could be formed, are often corroded or otherwise adversely affected by paints or solvents while suitable plastics materials which are likely to alleviate these effects from paint or solvent are generally regarded as unacceptably expensive. U.S. 2,076,549 discloses a plastics container assembly having an open topped container part with a liner which extends downwardly from a flange at the open top of the container part and which flange interconnects the liner to the container part. A top closure or lid is provided which screw engages with an external thread on a part of the liner which extends upwardly from the flange so that a sealed chamber is formed. The material of the liner may be different from that of the container part and selected as appropriate to resist detrimental action of particular material which is intended to be contained in the sealed chamber. With such a container assembly the plastics material of the liner is likely to be expensive as compared with that of the outer container part and it is an object of the present invention to provide a container assembly formed of plastics material comprising an outer container, a liner and a lid and which assembly alleviates the aforementioned difficulties and also permits a reduction in the amount of plastics material required in providing the liner. STATEMENT OF INVENTION & ADVANTAGES According to the present invention there is provided a container assembly comprising an outer open topped container part formed of a first plastics material having a base and an upwardly extending side wall; an open topped inner container part formed of a second plastics material and located and secured to provide a liner within the outer container part, said liner extending within the outer container part downwardly from a peripheral flange located at the open top of the outer container part and extending internally thereof; a removable lid having a closure face which forms a sealed chamber with said liner, CHARACTERISED IN THAT the internal peripheral flange is of the first plastics material and the closure face of the lid is of the second plastics material; an upper end part of the liner forms a peripheral seal with said flange, and a peripheral edge of the lid snap engages with the flange so that the closure face is in sealing abutment with the upper end part of the liner and the sealed chamber is wholly defined by the second plastics material. By the present invention the outer container part is preferably moulded of a relatively inexpensive structural plastics material such as polypropylene to have a shock resistant semi-rigid structure. The inner container part and the lid (or at least the closure face of the lid if that lid is not formed as a one piece moulding) may be formed of a plastics material such as polyethyleneteraphthalates (hereinafter known at PET) which may be regarded as unacceptably expensive to constitute the whole container assembly but has the advantage that it is practically unaffected by chemical or solvent action from a material such as paint, which is likely to be stored in the sealed chamber of the container assembly. The liner provided by the inner container part may be formed by blow moulding a parison, preferably to correspond, substantially, in both size and shape to the interior of the outer container part. Thus the inner container part may comprise substantially less plastics material than the outer container part and when received in the outer container part is supported to prevent liquid received in the inner container part from contacting the outer container part. The flange may be moulded as an integral part of the outer container part and the liner provided by the inner container part is secured to the flange to extend downwardly therefrom within the outer container part. The lid is fitted by snap engagement with the flange so that the closure face of the lid forms a seal with the material of the liner/inner container part. The inner container part may be secured to the flange of the outer container part by a compression fit, mechanical engagement (such as snap engagement between appropriately moulded recesses and projections on the respective parts) or bonding by way of adhesive or welding. Usually the inner container part will be secured to the outer container part solely around the internal periphery of the internal flange. If required support means such as internal ribs in the outer container part can be provided for the liner. The liner may be blow moulded directly into the outer container part or may be fitted as a moulded unit into the outer container part, possibly through an opening in the bottom of the outer container part which is subsequently closed by a base panel secured to the outer container part. DRAWINGS An embodiment of a container assembly for paint constructed in accordance with the present invention will now be described, by way of example only, with reference to the accompanying illustrative drawings in which: Figure 1 is a section showing the inner container part and the outer container part (in part only) of the assembly; Figure 2 is a section showing part of the assembly in Figure 1 with a lid fitted, and Figure 3 shows a modified form of flange on the outer container part. DETAILED DESCRIPTION OF DRAWINGS The paint container assembly shown has a generally cylindrical open topped outer container 1 moulded in polypropylene and comprising a base 2 carrying an upwardly extending cylindrical side wall 3. The container part 1 is open topped and the upper end of its side wall 3 is provided with an annular internal flange 4 integrally formed with that side wall. The flange 4 includes an annular rib 5 carrying a downwardly extending cylindrical skirt 6. Located within the outer container part is an open topped inner container part 7 blow moulded in PET to substantially conform to the internal dimensions of the outer container part and which is necked at 8 to be closely received within the skirt 6. For convenience of locating the liner 7, the base 2 is formed as a plate separately from the side wall 1 so that the liner can be inserted into the tube presented by the cylindrical wall 1 and thereafter the base plate 2 is secured to the side wall 1, conveniently by welding. The upper end or rim 9 of the liner neck is closely received within an annular rebate formed between the rib 5 and skirt 6. The liner neck 8 will usually be secured by an adhesive or otherwise to the skirt 6. For the purpose of closing the open top of the outer container, a dish shaped circular lid 10 is provided which is moulded in PET, advantageously in transparent PET so that the paint colour is discernible through the lid. The lid 10 includes a generally frusto conical side wall 11 having an external annular recess 12 formed between an annular abutment 13 and an external annular rib 14 of the lid. During fitting of the lid to close the assembly, the annular rib 5 snap engages within the annular recess 12. Following such snap engagement the rib 14 of the lid is urged by the resilience of the plastics material to bear against the neck 8 of the liner and thereby form an annular seal between the liner and the lid. The pressure of the rib 14 on the neck 8 additionally serves to retain the liner neck on the skirt 6 of the flange. Following engagement of the lid with the flange 4 as aforementioned, it will be apparent that a sealed chamber of PET material is defined between the lid 10 and liner 7 so that paint stored within the sealed chamber (and which may be corrosive to inexpensive polypropylene material) is prevented from contacting the polypropylene during storage by the PET barrier. Although PET is more expensive than polypropylene, it is likely to be resistive to corrosive attack from the paint and may represent a much smaller proportion than the polypropylene in the total amount of plastics in the assembly. It will be seen from the drawings that the annular rib 5 of the flange can conveniently serve for the removal of excess paint from a loaded brush which may be dipped into paint in the container. Although the polypropylene material of the rib 5 will be exposed to paint stored in the container once the lid is removed, it is unlikely that such exposure will be adequate to materially deteriorate the plastics material. In Figure 2, there is shown, for convenience, a second lid 10a which is identical to the lid 10, this second lid is illustrated merely to demonstrate the manner in which several lids may be stacked with the rib 14 of an upper lid in abutment with the immediately underlying lid to facilitate removal of the lids successively from the stack. The modification in Figure 3 shows the internal flange 4 moulded separately from the side wall 3. The flange 4 comprises concentric cylindrical skirts 20 and 21 interconnected by an annular radial web 22 and an array of circumferentially spaced, axially extending reinforcing webs 23. The annular web 22 and cylindrical skirt 21 converge to an internal annular rib 24 which is similar to the rib 5 in Figure 1 and is intended to snap engage within the annular recess 12 of the PET lid. The inner skirt 21 receives the neck of the liner 7. The outer skirt 20 of the flange 4 is provided with an external annular shoulder 25 which abuts the end of the wall 3. A close sliding fit of the outer skirt 20 of the flange 4 within the cylindrical wall 3 may be adequate to restrain the inner container in the outer container (particularly when radial pressure is applied to the flange 4 on fitting the lid 10) but if required the flange 4 of Figure 3 may be welded or otherwise bonded to the wall 3 or mechanically engaged therewith.

Claims: 1. A container assembly comprising an outer open topped container part (1) formed of a first plastics material having a base (2) and an upwardly extending side wall (3); an open topped inner container part (7) formed of a second plastics material and located and secured to provide a liner within the outer container part (1), said liner (7) extending within the outer container part (1) downwardly from a peripheral flange (4) located at the open top of the outer container part (1) and extending internally thereof; a removable lid (10) having a closure face which forms a sealed chamber with said liner, CHARACTERISED IN THAT the internal peripheral flange (4) is of the first plastics material and the closure face of the lid (10) is of the second plastics material; an upper end part (8) of the liner (7) forms a peripheral seal with said flange (4), and a peripheral edge (11) of the lid (10) snap engages with the flange (4) so that the closure face is in sealing abutment with the upper end part (8) of the liner and the sealed chamber is wholly defined by the second plastics material. 2. An assembly as claimed in claim 1 in which the lid (10) is a one piece moulding of the second plastics material. 3. An assembly as claimed in either claim 1 or claim 2 in which the internal flange (4) comprises a downwardly extending skirt (6) within which the upper end part (8) of the liner is closely received and the closure face of the lid (10) is in sealing abutment with the interior of said upper end part (8) of the liner. 4. An assembly as claimed in any one of the preceding claims in which the upper end part (8) of the liner has a rim (9) which is closely received in a rebate in the flange (4). 5. An assembly as claimed in any one of the preceding claims in which the internal flange (4) comprises an internal peripheral rib (5) and the peripheral edge (11) of the lid has an external peripheral recess (12) with which the rib (5) snap engages. 6. An assembly as claimed in claim 5 when appendant to claim 4 in which the skirt (6) of the flange (4) extends downwardly adjacent to the rib (5) of the flange and the rebate within which the liner rim (9) is received is formed between said rib (5) and skirt (6). 7. An assembly as claimed in any one of the preceding claims in which the upper end part (8) of the liner (7) is secured to the flange (4) to form a seal therewith by welding, bonding or adhesive. 8. An assembly as claimed in any one of the preceding claims in which the flange (4) is integrally moulded with the outer container part. 9. An assembly as claimed in any one of the preceding claims in which the liner (7) has a necked configuration so that the upper end part (8) of the liner is located on the neck part thereof and a major part of the liner is closely received within the outer container part (1). 10. An assembly as claimed in any one of the preceding claims in which the base (2) comprises a plate of the first plastics material which is formed separately from, and secured to, the side wall (3) to close a bottom end opening of the side wall said opening facilitating location of the liner (7) within the outer container part (1).

Inventors: HAINES, PETER REGINALD
Applicants: LIN PAC MOULDINGS LIMITED
Application year: 1988
Main classification: B65D6
IPC codes: B65D25, B29C49, B65D43, B65D6