Container, in particular a bottle, made of thermoplastic material having improved vertical load strength

Abstract

The present invention relates to a container (1), in particular a bottle, made of thermoplastic material manufactured by blow moulding or stretch blow moulding a heated preform, the container comprising a bottom (2) and a neck (3) which are connected to a body (4), the neck (3) and the bottom (2) being substantially rigid and the body (4) extending vertically and comprising an axially central part (5) surrounded by an axially lower part (6) and by an axially upper part (7) which form joining areas with the bottom (2) and the neck (3), at least one of the lower (6), central (5) and upper (7) parts of the body (4) comprising at least one flexible raised area (10a, 10b, 10c, 10d) and / or at least one rigid recessed area (11a, 11b), the container (1) being noteworthy in that the rigid recessed area (11a, 11b) comprises a plurality of flexible elements (15) so as to increase the internal pressure and thereby increase the vertical load strength value of the container (1).

Description

Container, in particular a bottle, made of thermoplastic material with improved vertical load resistance

[0001] The subject of the invention is a container, in particular of the bottle type, made of thermoplastic material, obtained by blow molding a plastic blank, either by thermal conditioning, then blow molding or stretching and blow molding of pre-injected preforms, or by extrusion then blow molding of a parison. More particularly, the present invention relates to a container of low weight and having resistance to longitudinal and / or transverse compression forces. State of the art

[0002] In the field of packaging, and more particularly in the packaging of liquids, such as water, it is well known to produce containers from thermoplastic materials, such as polyethylene terephthalate (PET), polypropylene (PP) or HDPE (high-density polyethylene). However, the price of these thermoplastic materials, and in particular PET, is constantly increasing significantly. One solution to reduce the production costs of containers is to reduce as much as possible the quantity of thermoplastic material used for their production. Thus, the current trend is to reduce the weight of containers, and consequently to reduce the quantity of thermoplastic material necessary for the production of a container, that is to say, we start from increasingly lighter blanks (preforms or parisons).

[0003] However, it is well known that these increasingly lightweight thermoplastic bottles have the disadvantage of offering low mechanical resistance in both the longitudinal and transverse directions.

[0004] Such lightweight bottles are described in particular in documents WO03 / 033361 and EP1468930.

[0005] Document WO03 / 033361 describes a container, in particular a bottle, made of thermoplastic material manufactured by blow molding or stretch blow molding of a heated preform, this container having a base and a neck connected to a body, said body comprising an axially central part surrounded by an axially lower part and by an axially upper part forming a connection zone respectively with the base and the neck, the axially central part being substantially rigid and the axially upper and lower parts being substantially deformable with shape memory, so that they return to their initial shape under the hydrostatic pressure of the liquid contents.

[0006] However, the body of this container does not have any gripping means and this known container is essentially intended to be used in a lying position as a fountain.

[0007] Also known is document EP1468930 which describes thin-walled containers made of semi-crystalline PET with a thickness of less than 0.1 mm comprising a central portion of narrowed diameter. More particularly, said container has an essentially ovoid overall shape and a complex three-dimensional shape essentially in the middle of the body with a diameter smaller than that of the rest of the body.

[0008] However, once opened, this container cannot be grasped without causing severe crushing which could cause the liquid product contained inside to spill. In addition, this container does not have sufficient longitudinal compressive strength, this compressive force being manifested when the bottles are stacked on top of each other during storage and transport.

[0009] Thus, the thin-walled containers according to the prior art are not arranged so that they can be stacked without causing the body of the container to be crushed and so that they can be grasped correctly without causing the body of the container to be crushed, which leads to spillage of the liquid product contained in the container, once the container is uncapped. In addition, the containers according to the prior art are sensitive to impacts or crushing, which result in whitish fold lines, scratches or marks that are likely to appear on the walls in the event of impacts. These defects are not visually acceptable, since the container could not be put on sale, customers preferentially purchasing containers without a visual defect rather than containers with a defect.

[0010] In order to overcome these drawbacks, containers with better resistance to longitudinal and / or transverse compression have already been devised. This is the case in particular with documents FR2625974 and FR2907763.

[0011] Document FR2625974 describes a bottle made of bi-oriented thermoplastic material which, to facilitate its handling on the packaging and distribution chain, has a generally square cross-section, rounded corners and a circular base. This bottle also has longitudinal ribs parallel to the longitudinal axis of the bottle and arranged between the rounded corners in such a way that the bottle resists without significant deformation, when filled, a compressive force applied along the longitudinal axis of the bottle.

[0012] Document FR2907763 describes a container, in particular a bottle, made of thermoplastic material manufactured by blow molding or stretch blow molding of a heated preform, this container having a bottom and a neck connected to a body. The neck and the bottom are substantially rigid and the body comprises an axially central part surrounded by an axially lower part and by an axially upper part forming connection zones respectively with the bottom and the neck, the axially central part being substantially rigid and the axially upper and lower parts being substantially deformable with shape memory, so that they return to their initial shape under the hydrostatic pressure of the liquid contents. More particularly, said lower and upper parts have areas stiffened by relief alternating with areas not stiffened by relief.

[0013] Although these bottles have better resistance to a compressive force applied along the longitudinal axis of the bottle, they are not strong enough for even lighter bottles, i.e. with increasingly thin walls.

[0014] Documents WO2004 / 080828 and US8939316 are also known, which describe containers having better resistance to longitudinal and / or transverse compression.

[0015] WO2004 / 080828 describes a plastic container having an optimal ratio of ring strength to top-fill strength, which comprises a neck section and a generally cylindrical main body section. The main body section comprises a side wall having a first plurality of generally vertical ribs. In addition, a second plurality of generally horizontal corrugated ribs are defined in the side wall. The generally horizontal corrugated ribs intersect the generally vertical ribs, thereby providing the container with improved strength characteristics.

[0016] US8939316 describes a blow-molded container which comprises a closable mouth portion, a side wall and a closed bottom. The material in the side wall portion is formed by blow-forming an injection-molded preform. Along an outer periphery of the container are arranged at least three gripping recesses. Between the gripping recesses are arranged in each case at least two longitudinal ribs oriented in a longitudinal direction of the container. The longitudinal ribs are separated from each other by a recess also extending in the longitudinal direction. Within each of the gripping recesses is arranged at least one peripheral rib which extends in a peripheral direction of the container.

[0017] Similarly, although these bottles have better resistance to a compressive force applied along the longitudinal axis of the bottle, they are not strong enough for even lighter bottles, i.e. with increasingly thin walls.

[0018] There is therefore a need for thermoplastic bottles which are even lighter and have greater resistance to longitudinal compression, said longitudinal compression force occurring when the bottles are stacked on top of each other during storage and transport, and to transverse compression, said transverse compression force occurring when the bottles are gripped at the central part of their body. Disclosure of the invention

[0019] One of the aims of the invention is therefore to overcome these drawbacks by proposing a container of simple and inexpensive design and whose resistance to longitudinal and transverse compression is improved.

[0020] For this purpose and in accordance with the invention, a container, in particular a bottle, is proposed, made of thermoplastic material manufactured by blow molding or stretch blow molding of a heated preform, said container comprising a bottom and a neck connected to a body, the neck and the bottom being substantially rigid and the body extending vertically and comprising an axially central part surrounded by an axially lower part and by an axially upper part forming connection zones with the bottom and the neck, at least one of the lower, central and upper parts of the body comprising at least one flexible raised zone and / or at least one rigid hollow zone; said container is remarkable in that at least one part of said rigid hollow zone extends substantially vertically, i.e.parallel to the vertical longitudinal axis of said container, and has a substantially rectangular shape to form at least one vertical beam which extends substantially from the bottom of the container towards the central part and in that said rigid hollow zone comprises a plurality of flexible elements so as to increase the internal pressure and thus increase the value of resistance to the vertical load of the container.

[0021] Preferably, said flexible elements of the hollow rigid zone extend horizontally, i.e. perpendicular to the vertical longitudinal axis of the container.

[0022] Furthermore, said flexible elements are made up of ribs.

[0023] Preferably, said ribs have a width decreasing from the bottom towards the central part.

[0024] Furthermore, said ribs have an increasing width from the central part towards the neck.

[0025] Preferably, said container comprises at least three vertical beams uniformly distributed around the body of the container.

[0026] Furthermore, the upper ends of said vertical beams are connected two by two by parts of the stiffened zone in the form of vaults.

[0027] Another subject of the invention relates to a mold for the manufacture of a container according to the invention by blow molding or stretch blow molding of a plastic blank.Said mold comprises at least one mold base capable of being movably mounted in a side wall which defines a cavity in the impression of a part of the container, said side wall comprising two half-molds each defining a half-impression of the body of the container and mounted in rotation relative to each other, between a so-called open position, in which the half-molds are angularly spaced from each other and the mold base is lowered relative to the half-molds to allow the introduction of the blank and the evacuation of the formed container, and a so-called closed position, in which the half-molds are applied against each other and trap the mold base between them to thus form the cavity and define the total impression of the container to be formed; said mold is remarkable in that the half-impressions of the side walls and / or the mold base are shaped to produce a container according to the invention.

[0028] Other advantages and characteristics will emerge more clearly from the following description of several variant embodiments, given as non-limiting examples, of the container according to the invention, with reference to the appended drawings in which:

[0029] is a perspective view from above of the container according to the invention,

[0030] is a side view of the container according to the invention shown in the,

[0031] is a side view of the container according to the invention shown on the following another angle of view,

[0032] is a perspective view from above of an alternative embodiment of the container according to the invention,

[0033] is a side view of the variant embodiment of the container according to the invention shown in the,

[0034] is a side view of the container according to the invention shown on the following another angle of view,

[0035] is an exploded perspective view of a mold for the production of a container according to the invention.

[0036] Method of carrying out the invention

[0037] In the following description of the container according to the invention, the same numerical references designate the same elements. The different views are not necessarily drawn to scale.

[0038] With reference to figures 1 to 3, the container 1 according to the invention, of the bottle type, is made of thermoplastic material manufactured by blow molding or stretch blow molding of a heated preform, not shown in the figures, and usually comprises a base 2, substantially rigid, and a neck 3, also substantially rigid, connected by a body 4.

[0039] Said body 4 comprises an axially central part 5 surrounded by an axially lower part 6 and by an axially upper part 7 forming connection zones respectively with the bottom 2 and the neck 3.

[0040] In order to allow easy gripping of the container, and without crushing, the central part 5 is substantially rigid and the axially upper and lower parts 6, 7 respectively are substantially flexible. It will be noted that by “flexible” zone is meant a zone which deforms more, for the same given pressure than a so-called “rigid” zone.

[0041] Said central part 5 is curved, that is to say its dimensions are smaller than those of the axially upper and lower parts 6, 7 respectively and comprises reinforcing means 8 in the form of a plurality of annular ribs 9. In this particular embodiment, said ribs 9 have a decreasing width from the bottom 2 towards the central part 5 and an increasing width from the central part 5 towards the neck 3.

[0042] It is obvious that the central part 5 may not be curved and / or may only include one annular rib 9 without departing from the scope of the invention.

[0043] Furthermore, the lower and upper parts 6, 7 respectively have flexible zones 10 in relief alternating with rigid zones 11 in hollow.

[0044] More precisely, the lower part 6 comprises a first flexible raised zone 10a extending from the bottom 2 of the container and comprising three zones of substantially triangular shapes uniformly distributed around the body 4, the points of said triangular zones being oriented towards the neck 3 of the container, and a second flexible raised zone 10b extending between the first rigid raised zone 10a and the central part 5 and having a substantially sinusoidal shape. Said flexible raised zones 10a and 10b delimit a rigid hollow zone 11a consisting of at least three vertical beams 12, that is to say beams 12 extending parallel to the vertical longitudinal axis of said container 1, uniformly distributed around the body 4, from the bottom 3 of the container 1 in the direction of the central part 5, said beams 12 being connected two by two by parts of the rigid hollow zone 11a in the form of vaults 13.Said beams 12 have a substantially rectangular shape; However, it goes without saying that the latter may have a square or trapezoidal shape, for example, without departing from the scope of the invention.

[0045] Advantageously, the bottom 2 is separated from the flexible raised zone 10a by an annular groove 14 in order to isolate said bottom 2 and thus preserve the mechanical properties of said bottom.

[0046] In addition, said rigid hollow zone 11a comprises a plurality of flexible elements 15 so as to increase the internal pressure and thus increase the value of resistance to the vertical load. In this particular embodiment, said flexible elements 15 consist of a plurality of ribs 16, in relief, extending horizontally, i.e. perpendicular to the vertical longitudinal axis of the container.

[0047] Said ribs 16 have a width decreasing from the bottom 2 towards the central part 5.

[0048] It goes without saying that the flexible elements 15 may consist of a plurality of grooves, in hollow, in place of the ribs 16, in relief, without departing from the scope of the invention. Furthermore, said ribs 16 or the grooves may have a constant width without departing from the scope of the invention.

[0049] Thus, the combination of the flexible elements 15 and the rigid hollow zone 11a and more particularly the beams 12 makes it possible to increase the internal pressure in the container 1 and thus to increase the value of resistance to the vertical load, commonly called "topload". The flexible raised zone 10a extending between two beams 12 is thus intended to swell under the internal pressure, making it possible to deform locally by increasing the "topload" while preserving the initial shape of the container 1.

[0050] Furthermore, the upper part 7 comprises a first flexible raised zone 10c extending from the central part 5 towards the neck 3 and having a substantially sinusoidal shape, and a second flexible raised zone 10d extending above the first flexible raised zone 10c to the neck 3, the first flexible raised zone 10c and the second flexible raised zone 10d delimiting a rigid annular hollow zone 11b of substantially sinusoidal shape.

[0051] Said rigid hollow zone 11b comprises a plurality of flexible elements 14 so as to increase the internal pressure and thus increase the value of resistance to the vertical load. In this particular embodiment, said flexible elements 15 are constituted in the same way as previously of a plurality of ribs 16, in relief, extending horizontally, i.e. perpendicular to the vertical longitudinal axis of the container 1.

[0052] Said ribs 16 have an increasing width from the central part 5 towards the neck 3. In the same way as previously, it is obvious that the flexible elements 15 may consist of a plurality of grooves, in hollow, in place of the ribs 16, in relief, without departing from the scope of the invention. Furthermore, said ribs 16 or the grooves may have a constant width without departing from the scope of the invention.

[0053] Incidentally, the second flexible raised zone 10d comprises annular grooves 17 extending horizontally between the central part 5 and the neck 3. In this particular embodiment, said flexible raised zone 11d comprises 5 annular grooves 16; however, it may comprise any number, or even none, without departing from the scope of the invention.

[0054] According to an alternative embodiment with reference to figures 4 to 6, the container 1 according to the invention, of the bottle type, is made of thermoplastic material manufactured by blow molding or stretch-blow molding of a heated preform, not shown in the figures, and comprises, in the same way as previously, a base 2, substantially rigid, and a neck 3, also substantially rigid, connected by a body 4.

[0055] Said body 4 comprises an axially central part 5 surrounded by an axially lower part 6 and by an axially upper part 7 forming connection zones respectively with the bottom 2 and the neck 3.

[0056] In order to allow easy gripping of the container, and without crushing, the central part 5 is substantially rigid and the axially upper and lower parts 6, 7 respectively are substantially flexible.

[0057] Said central part 5 is curved, and comprises reinforcing means 8 in the form of a plurality of annular ribs 9. In this particular embodiment, said ribs 9 have a width decreasing from the bottom 2 towards the central part 5 and an increasing width from the central part 5 towards the neck 3.

[0058] It is obvious that the central part 5 may not be curved and / or may only include one annular rib 9 without departing from the scope of the invention.

[0059] Furthermore, the lower part 6 comprises a first flexible raised zone 10a extending from the bottom 2 of the container and comprising three zones of substantially trapezoidal shapes uniformly distributed around the body 4, the small bases of said trapezoidal zones being oriented towards the neck 3 of the container 1, and separated two by two by vertical beams 12, that is to say beams 12 extending parallel to the vertical longitudinal axis of said container 1, uniformly distributed around the body 4, from a rigid hollow zone 11a extending from the central part 5. Said beams 12 have a substantially rectangular shape; However, it goes without saying that the latter may have a square or trapezoidal shape, for example, without departing from the scope of the invention.

[0060] Advantageously, the bottom 2 is separated from the flexible raised zone 10a by an annular groove 14 in order to isolate said bottom 2 and thus preserve the mechanical properties of said bottom.

[0061] In addition, said rigid hollow zone 11a comprises a plurality of flexible elements 15 so as to increase the internal pressure and thus increase the value of resistance to the vertical load. In this particular embodiment, said flexible elements 15 consist of a plurality of ribs 16, in relief, extending horizontally, i.e. perpendicular to the vertical longitudinal axis of the container.

[0062] Said ribs 16 have a width decreasing from the bottom 2 towards the central part 5.

[0063] It goes without saying that the flexible elements 15 may consist of a plurality of grooves, in hollow, in place of the ribs 16, in relief, without departing from the scope of the invention. Furthermore, said ribs 16 or the grooves may have a constant width without departing from the scope of the invention.

[0064] Furthermore, the upper part 7 comprises a flexible raised zone 10c extending from the central part 5 towards the neck 3 and having a lower edge of substantially sinusoidal shape.

[0065] Thus, the lower edge of said flexible raised zone 10c of the upper part 7 and the upper edge of the flexible raised zone 10 delimit the rigid hollow zone 11a. In said rigid hollow zone 11b, said ribs 15 have an increasing width from the central part 5 towards the neck 3 and a decreasing width from the bottom 3 towards the central part 5.

[0066] Incidentally, the flexible raised zone 10c comprises annular grooves 17 extending horizontally between the central part 5 and the neck 3. In this particular embodiment, said flexible raised zone 11d comprises 5 annular grooves 17; however, it may comprise any number, or even none, without departing from the scope of the invention. Furthermore, the flexible raised zone 10a of the lower part 6 also comprises helical grooves 18 or, possibly, annular grooves.

[0067] With reference to the, a molding unit 23 according to the invention is described for forming, from a blank, usually a preform, not shown in the figure, a container 1 such as a bottle or a can, for example, according to the invention as described previously.

[0068] Said molding unit 23, with reference to the, comprises a mold 24 provided with a side wall 25 which defines a cavity 26 in the impression of a part of the container. Said mold 24 further comprises a bottom 27 in the impression of the bottom of the container, said mold 24 being made of metal, for example steel or aluminum (this term also covering aluminum alloys). The cavity 26, and ultimately the container 1, extends along a main axis X which defines a vertical direction. Any plane perpendicular to the main axis X is said to be horizontal.According to an embodiment illustrated in the drawings, the side wall 25 comprises two half-molds 24A, 24B each defining a half-cavity 28A, 28B of the body of the container and mounted to rotate relative to each other about a common axis formed by a hinge, not shown in the figures, between an open position, in which the half-molds 24A, 24B are angularly spaced from each other and the mold base 27 is lowered relative to the half-molds 24A, 24B to allow the introduction of the blank and the evacuation of the formed container, and a closed position, in which the half-molds 24A, 24B are applied against each other and trap between them the mold base 27 to thus form the cavity 26 and define the cavity of the container to be formed.Thus, said mold base 27 is capable of being mounted movably in the mold 24 comprising two walls that are movable relative to each other and intended to form the body of the container, said movable mold base 27 pushing the plastic material constituting the container towards its opening. The half-cavities 28A, 28B of the side walls 25 and / or the mold base 27 are shaped to produce a container 1 according to the invention as described previously.

[0069] Finally, it is clear that the examples just given are only specific illustrations and are in no way limiting as to the fields of application of the invention.

Claims

Container (1), in particular a bottle, made of thermoplastic material manufactured by blow molding or stretch-blow molding of a heated preform, said container comprising a bottom (2) and a neck (3) connected to a body (4), the neck (3) and the bottom (2) being substantially rigid and the body (4) extending vertically and comprising an axially central part (5) surrounded by an axially lower part (6) and by an axially upper part (7) forming connection zones with the bottom (2) and the neck (3), at least one of the lower (6), central (5) and upper (7) parts of the body (4) comprising at least one flexible raised zone (10a, 10b, 10c, 10d) and / or at least one rigid hollow zone (11a, 11b), characterized in that at least one part of said rigid hollow zone (11a, 11b) extends substantially vertically, i.e.parallel to the vertical longitudinal axis of said container (1), and has a substantially rectangular shape to form at least one vertical beam (12) which extends substantially from the bottom (2) of the container (1) towards the central part (5) and in that said rigid hollow zone (11a, 11b) comprises a plurality of flexible elements (15) so as to increase the internal pressure and thus increase the value of resistance to the vertical load of the container (1). Container (1) according to claim 1 characterized in that said flexible elements (15) of the hollow rigid zone (11a, 11b) extend horizontally, i.e. perpendicular to the vertical longitudinal axis of the container (1). Container (1) according to any one of claims 1 or 2, characterized in that said flexible elements (15) consist of ribs (16). Container (1) according to claim 3, characterized in that said ribs (16) have a width decreasing from the bottom (2) towards the central part (5). Container (1) according to any one of claims 3 or 4, characterized in that said ribs (16) have an increasing width from the central part (5) towards the neck (3). Container (1) according to any one of claims 1 to 5, characterized in that it comprises at least three vertical beams (12) uniformly distributed around the body (4) of the container (1). Container (1) according to claim 6 characterized in that the upper ends of said vertical beams (12) are connected two by two by parts of the rigid hollow zone (11a, 11b) in the form of vaults (13). Mold (24) for manufacturing a container (1) by blow molding or stretch blow molding of a plastic blank, said mold (24) comprising at least one mold base (27) capable of being movably mounted in a side wall (25) which defines a cavity (26) in the impression of a part of the container (1), said side wall comprising two half-molds (24A, 24B) each defining a half-impression (28A, 28B) of the body (2) of the container (1) and mounted in rotation relative to each other, between a so-called open position, in which the half-molds (24A, 24B) are angularly spaced from each other and the mold base (27) is lowered relative to the half-molds (24A, 24B) to allow the introduction of the blank and the evacuation of the container (1) formed, and a so-called closed position, in which the half-molds (24A,24B) are applied against each other and trap between them the mold base (27) to thus form the cavity (26) and define the total imprint of the container (1) to be formed, characterized in that the half-imprints (28A, 28B) of the side walls and / or the mold base (27) are shaped to produce a container (1) according to any one of claims 1 to 7.,

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