CA1114756A - Plastics container - Google Patents
Plastics containerInfo
- Publication number
- CA1114756A CA1114756A CA321,638A CA321638A CA1114756A CA 1114756 A CA1114756 A CA 1114756A CA 321638 A CA321638 A CA 321638A CA 1114756 A CA1114756 A CA 1114756A
- Authority
- CA
- Canada
- Prior art keywords
- layer
- lid
- container according
- container
- layers
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Closures For Containers (AREA)
Abstract
7.
ABSTRACT
A container having a body and a lid is integrally moulded in the open condition from a thermoplastic laminate comprising a relatively flexible layer; preferably on the inside, and a relatively rigid layer. The rigid layer has a cut or line of weakening along the intended hinge line. Preferably, when the body and lid are first closed, the rigid layer fractures along the intended hinge line. The body and lid in use are therefore hinged together by the inner flexible layer.
ABSTRACT
A container having a body and a lid is integrally moulded in the open condition from a thermoplastic laminate comprising a relatively flexible layer; preferably on the inside, and a relatively rigid layer. The rigid layer has a cut or line of weakening along the intended hinge line. Preferably, when the body and lid are first closed, the rigid layer fractures along the intended hinge line. The body and lid in use are therefore hinged together by the inner flexible layer.
Description
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.
PLASTICS CONTAINER
.
This invention relates to containers made of plastics material, and more particularly to containers comprising a body and a lid hinged thereto and integrally moulded from thermoplastic material.
According to the present invention, there is provided a container comprising a body and at least one lid or other panel hinged thereto, the container being `10 integrally moulded ln the open condition from thermoplastic sheet material, the sheet material being a laminate of at least two thermoplastic layers~ a first layer comprising a flexible relatively non-rigid material, and a second layer comprising relatively rigid material, one or more cuts or lines of weakening being formed in said second layer along the intended hinge line between body and panel such that when the body and panel are ~`
hinged from the open to the closed condition, said second :; layer fractures along the intended hinge line, and the body and panel are joined by the relatively flexible plastics material of said first layer thereof.
More than one flexible layer may be provided if . I .
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PLASTICS CONTAINER
.
This invention relates to containers made of plastics material, and more particularly to containers comprising a body and a lid hinged thereto and integrally moulded from thermoplastic material.
According to the present invention, there is provided a container comprising a body and at least one lid or other panel hinged thereto, the container being `10 integrally moulded ln the open condition from thermoplastic sheet material, the sheet material being a laminate of at least two thermoplastic layers~ a first layer comprising a flexible relatively non-rigid material, and a second layer comprising relatively rigid material, one or more cuts or lines of weakening being formed in said second layer along the intended hinge line between body and panel such that when the body and panel are ~`
hinged from the open to the closed condition, said second :; layer fractures along the intended hinge line, and the body and panel are joined by the relatively flexible plastics material of said first layer thereof.
More than one flexible layer may be provided if . I .
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desired. For example, a second flexible layer may beprovided on the outside of the container. The flexible layer or layers may for example be a vinyl polymer such as polyvinyl chloride, or a polyolefin, such as polyethylene or polypropylene. The rigid layer may for example be polystyrene. If necessary, an adhesive layer may be provided between adjacent thermoplastic layers to secure them adequately together in cases where the thermoplastic layers are not sufficiently compatible.
1~ In order that the invention may be more clearly understood, various embodiments will now be described with reference to the accompanying drawings, wherein:
Fig. 1 shows a perspective view of a formed container prior to closure, Fig. 2 shows a cross-section along the line II-II
of Fig. 1, Fig. 3 shows a similar cross-section with the container in the closed condition, Fig. 4 shows a detail cross-sectional view o~ the hinge in the closed container of Fig. 3, Fig. 5 shows diagrammatically a cross-section through a second embodiment of container, and Fig. 6 shows diagrammatically a cross-section through part of a thir~ embodiment of container.
Referring to Figs. 1 to 4 of the drawings; the container is moulded from a single sheet of thermoplastic materia~ which comprises a laminate of 20 thou polystyrene and 3 to 5 thou poly~thylene, with an intermediate adhesive layer, since polystyrene and polyethylene are insufficiently compatible to adhere together satisfactorily. The laminate is suitably formed by coextruding the three layers from a single extruder, according to known technlques.
The container comprises a tray shaped body part 10 and a tray shaped lid part 12, both trays being of equal depth, and separated by a strip 14 which is at the same le~el as the outturned flange 16 around the rim of the ,,. :. . : ~ . ' . ' ', -- . . : , .
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moulding. It is moulded so th~t the polystyrene layer is on the outside of the tray and the polyethylene layer on the inslde. The moulding is trimmed to the desired outline in plan by a conventional cutting die of reciprocating or rotary type. The same die that cuts the flange 16 is also provided with elements to form a line 18 of intermittent cuts along the intended hinge line which extends centrally along the strip 14. Suitably, the cuts 18 are about twice as long as the intermediate uncut regions. Instead of intermittent cuts, spaced apertures could be arranged to provide a line of weakening. Since the relatively rigid polystyrene layer form~ the outside of the tray, the cutting die is preferably applied to the undersurface of the tray 80 t5 that it will cut cleanly through the polystyrene. If it is applied to the upper ~urface, it may merely distort the relatively flexible polyethylene,;and not effect a clean cut.
When the two halves 10,12 are folded over onto each 2~ other as in Fig. 3, the uncut regions of the polystyrene layer 20 ~long the line 18 fracture under the strain, as can be seen i~ Fig. 4, but the relatively ~lexible polyethylene layer 22 remains coherent in those regions, and therefore hingedly ~oins the two parts. The container will thus ~tay clo~ed. The outline of the lid part 12 may be rather less than that of the body part 10 as ~hown i~ Fig. 1, 80 that it~ free edge fit~ within the body part in the clo~ed condition as can be seen from Fig. 3. It may be retained in that condition by a shalloW inwardly pro~ecting lip 24 formed along the corresponding part of the rim of the body 10 . An internal ledge 26 and a lip 28 upstanding therefrom serve to limit the extent o~ entry of the lid part and maintain it in engagement with the lip 24.
It is particularly edvantageous to have the strip , .
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14 in the same plane as the flange 16, since the cuts 18 can then be ea~ily formed at the same time as the flange 16 is cut to shape. If the strip 14 and flange 16 were on different levels, a more complicated tooling arrangement would be required, or else the cutting would have to be carried out in two stages.
The hinge formed by the polyethylene layer is in general not very durable, but this is quite satisfactory where the container has to b~ opened and closed only a few timesl for example in disposable containers such as those used for packaging airline meals. Where a more durable hinge $s required a heavier gauge of polyethylene is provided or a dif~erent flexible plastics material may be employed, such as polypropylene.
Another advantage of having a two layer construction is that, in the case of food containers for example, the inner flexible layer can be of a m~terial which is acceptable for contact with food, while the outer layer does not require to be of the same standard.
Instead of intermittent full cuts on the line 18, o single half cut or serie~ of half cut~ could be form~d in the polystyrene layer to provlde a line of weakening whlch will cause the material to ~racture when the container is closed.
Instead of a tray having a single lid, a multiplicity of li~ sections are also envisaged which may hinge from opposite sides or each ~ide of the body part to form a composite lid. Alternatively a single l~ may have a hinge running across it so that one half only of the lid can be opened if des~red.
In Fig. 5, in addition to tray-shaped body and lid parts 10,12, there is a ~econdary lid part 12' hinged to the opposite edge of the body part at 18' in the same manner as the lid part 12, and i~ arranged to fold over 35 the body part 10 before the lid part 12 i8 folded o~er, .. , . , ., ~ .. -, , , .. -. . : . . .. .. .. . . . ..
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as shown. The free edge of the secondary lid part 12' has a flange 13 which i~ trapped between the strips 14 when the lid part 12t ia folded over. Ad~ncent the hinge 18', the secondary lid part 12' i~ provided with a re-entrant portion 19 into which a similarly re-entrant portion 21 near the free edge of the lid part 12 is a snap fit to keep the lid part 12 closed.
In Fig. 6, the container is similar to thst of Fig.
5, except that the secondary lid part 12' is omitted apart from the re-entrant portion 19 which still serves to retain the lid 12.
The hinge construction previously described also allows heavier gauge relatively rigid material of say 20 - 40 thou in thickness to be folded.
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desired. For example, a second flexible layer may beprovided on the outside of the container. The flexible layer or layers may for example be a vinyl polymer such as polyvinyl chloride, or a polyolefin, such as polyethylene or polypropylene. The rigid layer may for example be polystyrene. If necessary, an adhesive layer may be provided between adjacent thermoplastic layers to secure them adequately together in cases where the thermoplastic layers are not sufficiently compatible.
1~ In order that the invention may be more clearly understood, various embodiments will now be described with reference to the accompanying drawings, wherein:
Fig. 1 shows a perspective view of a formed container prior to closure, Fig. 2 shows a cross-section along the line II-II
of Fig. 1, Fig. 3 shows a similar cross-section with the container in the closed condition, Fig. 4 shows a detail cross-sectional view o~ the hinge in the closed container of Fig. 3, Fig. 5 shows diagrammatically a cross-section through a second embodiment of container, and Fig. 6 shows diagrammatically a cross-section through part of a thir~ embodiment of container.
Referring to Figs. 1 to 4 of the drawings; the container is moulded from a single sheet of thermoplastic materia~ which comprises a laminate of 20 thou polystyrene and 3 to 5 thou poly~thylene, with an intermediate adhesive layer, since polystyrene and polyethylene are insufficiently compatible to adhere together satisfactorily. The laminate is suitably formed by coextruding the three layers from a single extruder, according to known technlques.
The container comprises a tray shaped body part 10 and a tray shaped lid part 12, both trays being of equal depth, and separated by a strip 14 which is at the same le~el as the outturned flange 16 around the rim of the ,,. :. . : ~ . ' . ' ', -- . . : , .
- , ~ -:
.
. ~ , .
~ ............ .~ :
moulding. It is moulded so th~t the polystyrene layer is on the outside of the tray and the polyethylene layer on the inslde. The moulding is trimmed to the desired outline in plan by a conventional cutting die of reciprocating or rotary type. The same die that cuts the flange 16 is also provided with elements to form a line 18 of intermittent cuts along the intended hinge line which extends centrally along the strip 14. Suitably, the cuts 18 are about twice as long as the intermediate uncut regions. Instead of intermittent cuts, spaced apertures could be arranged to provide a line of weakening. Since the relatively rigid polystyrene layer form~ the outside of the tray, the cutting die is preferably applied to the undersurface of the tray 80 t5 that it will cut cleanly through the polystyrene. If it is applied to the upper ~urface, it may merely distort the relatively flexible polyethylene,;and not effect a clean cut.
When the two halves 10,12 are folded over onto each 2~ other as in Fig. 3, the uncut regions of the polystyrene layer 20 ~long the line 18 fracture under the strain, as can be seen i~ Fig. 4, but the relatively ~lexible polyethylene layer 22 remains coherent in those regions, and therefore hingedly ~oins the two parts. The container will thus ~tay clo~ed. The outline of the lid part 12 may be rather less than that of the body part 10 as ~hown i~ Fig. 1, 80 that it~ free edge fit~ within the body part in the clo~ed condition as can be seen from Fig. 3. It may be retained in that condition by a shalloW inwardly pro~ecting lip 24 formed along the corresponding part of the rim of the body 10 . An internal ledge 26 and a lip 28 upstanding therefrom serve to limit the extent o~ entry of the lid part and maintain it in engagement with the lip 24.
It is particularly edvantageous to have the strip , .
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4.
14 in the same plane as the flange 16, since the cuts 18 can then be ea~ily formed at the same time as the flange 16 is cut to shape. If the strip 14 and flange 16 were on different levels, a more complicated tooling arrangement would be required, or else the cutting would have to be carried out in two stages.
The hinge formed by the polyethylene layer is in general not very durable, but this is quite satisfactory where the container has to b~ opened and closed only a few timesl for example in disposable containers such as those used for packaging airline meals. Where a more durable hinge $s required a heavier gauge of polyethylene is provided or a dif~erent flexible plastics material may be employed, such as polypropylene.
Another advantage of having a two layer construction is that, in the case of food containers for example, the inner flexible layer can be of a m~terial which is acceptable for contact with food, while the outer layer does not require to be of the same standard.
Instead of intermittent full cuts on the line 18, o single half cut or serie~ of half cut~ could be form~d in the polystyrene layer to provlde a line of weakening whlch will cause the material to ~racture when the container is closed.
Instead of a tray having a single lid, a multiplicity of li~ sections are also envisaged which may hinge from opposite sides or each ~ide of the body part to form a composite lid. Alternatively a single l~ may have a hinge running across it so that one half only of the lid can be opened if des~red.
In Fig. 5, in addition to tray-shaped body and lid parts 10,12, there is a ~econdary lid part 12' hinged to the opposite edge of the body part at 18' in the same manner as the lid part 12, and i~ arranged to fold over 35 the body part 10 before the lid part 12 i8 folded o~er, .. , . , ., ~ .. -, , , .. -. . : . . .. .. .. . . . ..
- , . . . . , . .-- : . - , - ~ .. . .
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.
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as shown. The free edge of the secondary lid part 12' has a flange 13 which i~ trapped between the strips 14 when the lid part 12t ia folded over. Ad~ncent the hinge 18', the secondary lid part 12' i~ provided with a re-entrant portion 19 into which a similarly re-entrant portion 21 near the free edge of the lid part 12 is a snap fit to keep the lid part 12 closed.
In Fig. 6, the container is similar to thst of Fig.
5, except that the secondary lid part 12' is omitted apart from the re-entrant portion 19 which still serves to retain the lid 12.
The hinge construction previously described also allows heavier gauge relatively rigid material of say 20 - 40 thou in thickness to be folded.
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Claims (9)
1. A container comprising a body and at least one lid or other panel hinged thereto, the container being integrally moulded in the open condition from thermoplastic sheet material, the sheet material being a laminate of at least two thermoplastic layers, a first layer comprising a flexible relatively non-rigid material, and a second layer comprising relatively rigid material, one or more cuts or lines of weakening being formed in said second layer along the intended hinge line between body and panel such that when the body and panel are hinged from the open to the closed condition, said second layer fractures along the intended hinge line, and the body and panel are joined by the relatively flexible plastics material of said first layer thereof.
2. A container according to claim 1 wherein said first layer lies on the inside of the container relative to said second layer.
3. A container according to claim 1 wherein a series of intermittent cuts extend through both layers along the intended hinge line prior to hinging from the open to the closed condition.
4. A container according to claim 1 wherein two rigid layers sandwich a flexible layer.
5. A container according to claim 1 wherein an adhesive layer is provided between adjacent thermoplastic layers to secure them together.
6. A container according to claim 1 wherein the flexible layer or layers comprise a vinyl polymer or polyolefin.
7. A container according to claim 1 wherein the rigid layer or layers comprise polystyrene.
8. A container according to claim 1 wherein the thermoplastic sheet material is formed to provide also a strip portion along the edge of the body remote from the lid and joined to the body one or more cuts or lines of weakening as aforesaid so that the strip portion can be hinged upwardly before closing the lid, the strip portion being shaped to provide a re-entrant cross-section which engages a co-operating formation inside the lid to retain the lid in the closed condition.
9. A container according to claim 8 wherein the strip portion is part of a secondary lid moulded from the sheet material and which extends over the body to lie beneath the first lid when the strip portion is hinged upwardly.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB647178 | 1978-02-17 | ||
| GB6471/78 | 1978-02-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1114756A true CA1114756A (en) | 1981-12-22 |
Family
ID=9815085
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA321,638A Expired CA1114756A (en) | 1978-02-17 | 1979-02-16 | Plastics container |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1114756A (en) |
| ZA (1) | ZA79645B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8701919B2 (en) | 2010-07-16 | 2014-04-22 | Cascades Canada Ulc | Plastic container |
-
1979
- 1979-02-13 ZA ZA79645A patent/ZA79645B/en unknown
- 1979-02-16 CA CA321,638A patent/CA1114756A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8701919B2 (en) | 2010-07-16 | 2014-04-22 | Cascades Canada Ulc | Plastic container |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA79645B (en) | 1980-02-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |