EP0575272B1 - Plastic tube having a rupturable membrane, said tube with a capsule and its uses - Google Patents

Abstract

The invention relates to a tube (1) whose head (2) includes a leaktight cover (5) which can be torn off by twisting, characterised in that this cover has a side surface (5) of polygonal outline (6) inclined by less than 10 DEG to the axis (16) of the tube (1), and a tearing region (10) lying between the side surface (50) and an inner surface (11) of the cover (5), including at least one thin portion of minimum thickness from 0.05 to 0.18 mm and at least one portion (9, 9') which is at least 1.5 times thicker. A further subject of the invention is the tube (1) accompanied by a cap (20) preserving the integrity of the perimeter of the cover and including a key (24) engaging with the cover for tearing it off by twisting, as well as its use in particular for storing and dispensing liquids in calibrated drops. The tube is used typically for storing and dispensing medical or cosmetic liquids. <IMAGE>

Description

The invention relates to a plastic tube surmounted by a tearable lid sealingly closing its outlet orifice, this tube possibly being fitted with a stopper comprising a key making it possible to fit and tear this lid by rotation.

EP-B-119145 and its equivalent US-A-4527700 disclose such a tube associated with a cap interlocking with internal reliefs the reliefs carried by the lateral surface of the cover. The base of the cover is connected by a tearable zone at the edge of the orifice of the neck of the tube, and the rotation of the cap fitted on the cover by its complementary reliefs makes it possible to drive the cover by breaking said area by twisting. . The cover is retained in the cover when it is forced into the interior reliefs of the cover. The diameter of the orifice was typically 2.5 to 10 mm.

In the case of orifices of often smaller diameter, typically from 1.2 to 4 mm, the rigidity of the sealed and tearable seal poses a problem as well as the ease of its gripping. GB-A-2 039 267 discloses a solution incorporating the idea of driving by rotation of a tearable lid and well suited to the small diameters of orifice targeted. However, the orifice obtained after tearing by rotation of the cover is in this case bordered by a tormented and non-reproducible breaking surface. If the tear was made without care, the damaged surface is so tormented that it does not allow a hermetic sealing of the capsule in the event of multiple uses. In addition, in the case of tubes of products to be delivered in drops, such a tormented and non-reproducible rupture surface, participating in the formation and detachment of the drops, is unsuitable for the formation of calibrated drops. In addition, this portion of detachment of the drops should preferably be protected throughout the use of the tube.

The Applicant has sought to develop a tear-proof seal tube which overcomes these problems.

STATEMENT OF THE INVENTION

The subject of the invention is a plastic tube having a head surmounted by a tight seal which can be torn by torsion, said cover having, up to its base connecting to said head, a lateral surface of polygonal outline, this surface being formed. by generators inclined by less than 10 ° on the axis of the tube away from said base, said cover having a tearing zone comprised between said lateral surface and an interior surface having circular sections perpendicular to said axis, these surfaces delimiting together at least one thin portion, characterized in that said at least one thin portion has a minimum thickness of between 0.05 and 0.18 mm and in that said lateral and interior surfaces (6 and 11) together define at least one thick portion, maximum thickness at minus 1.5 times stronger than said minimum thickness.

Thanks to the structure produced, the cover is sufficiently rigid until it connects with the head of the tube. The thicker portions of its internally hollow base provide this rigidity and facilitate the injection and obtaining of much thinner and nevertheless compact and tight intermediate parts, forming sites for initiation of torsional rupture. The cover being thus rigid and having a cylindrical or slightly conical shape, its gripping, preferably its fitting by a suitable key, is facilitated and the manipulations are not likely to cause it to bend and to damage its immediate periphery.

As in practice, there is to be done for the product contained approval tests on each material making up the interior of the tube, the tube head provided with the cover according to the invention is preferably overmolded on a skirt, the inner surface is formed by a plastic material identical to that of the head. And to obtain a tear in the ductile type cover and without residual deformation affecting its immediate periphery, preferably chosen as common plastic material for the overmolded head and for at least the interior of the skirt, is low density polyethylene of specific gravity between 0.88 and 0.93 g / cm³, or linear low density polyethylene.

According to a typical solution, simple to produce and giving a particularly satisfactory rigidity and tearability, the external surface of the tearing zone has a square contour and its hollow internal surface has perpendicular to the longitudinal axis of the tube and of the cover of the successive circular sections centered with respect to this square external surface, the progressive thinning and thickening of the wall comprised between these external and internal surfaces resulting in a maximum thickness of each of the two thick portions 2.5 to 4 times greater than the minimum thickness of each of the two thin portions between these thick portions. Said hollow interior surface is typically of revolution around said axis.

In the case of tubes for the delivery of a liquid in the form of drops, the base of the cover is connected to the head of the tube in an annular depression flared from this head, the diameter of the flush end of this depression being less than 2 mm larger than the outside width of the base of the cover and this cover projecting beyond this end by a height at least equal to its diameter. The relief of the cover protects the depression, which is the immediate periphery of its base, from damage which could be caused by manipulation. The side wall of the depression is typically frustoconical and constitutes the top of a truncated cone of drop formation which will be completed, downwards and inside, by the tear surface of the seal produced by the opening of the tube. The micro-asperities of this tearing surface then become sites for attachment of the drops of liquid, allowing them to form more easily and to grow by giving drops calibrated at 19 to 21 drops per cm³. Typically, the diameter of the flush end of the depression is between 2.5 and 7 mm, the external width of the base of the cover being between 2 and 6 mm.

In general, the inner surface of the cover is or belongs to a vault forming the back of the cover, this vault having a low height relative to the height of the cover and typically less than 1.3 mm and connecting to a circular cylindrical axial interior surface forming part of the orifice of the tube after tearing of the cover.

In the case where the base of the cover is surrounded by the flared annular depression already described, this preferably has a frustoconical lateral surface which will be extended by the lateral surface of rupture of the seal, which surface itself is substantially frustoconical , forming a drop forming surface succeeding as described above to a circular cylindrical axial inner surface of the tube head, the assembly allowing the expulsion of calibrated liquid drops.

The cover of the tube can be pinched or embedded by any means and then broken by twisting. Preferably, the tube is accompanied or equipped with a capsule which covers the head of the tube and the cover, the capsule then having no contact with this cover, and this capsule preferably has at its top a hollow cavity constituting a key which can fit the cover by immobilizing it in rotation relative, when the capsule is released from the tube and turned upside down, and making it possible to break the cover by rotation of the capsule. For the rotational drive to occur correctly, there is axial support of the inverted capsule on the head of the tube, and it is desirable that the drive surface of the cover has a height at least equal to 2 times the external width of its base, and furthermore that the conicity of the cover, this widening towards its base, is small, having as already indicated a ½ cone angle less than 10 °.

When this ½ angle is less than 5 ° or zero, the bottom fitting is done by simple pressing. Preferably for the cleanliness of a room or the environment, the generators of the lateral surface of the cover are inclined at less than 2 ° on the axis, the key of the tube then fully fitting the cover with a small clearance, preferably between 0.05 and 0.2 mm in diameter, and retaining it there after its rupture. It can be noted that this retention is linked to the polygonal shape and to the relative length of the embedding of the cover in the capsule and occurs without there having been necessarily.

In order to preserve even better the state of the flared annular depression bordering the cover, it is recommended to equip the top of the capsule with an outer end cone surrounding its cavity or hollow key, this cone fitting in the annular depression when the key of the capsule fits the cover.

According to another improvement to the capsule, the state of the flared annular depression is better preserved during storage of the tube capped with this capsule, by providing on the head of the tube a peripheral annular groove which surrounds the flared annular depression, as well as in the capsule attaching to the tube for example by screwing, an interior annular preferably annular rib which comes to be embedded in said annular groove in position for fixing at the bottom of the capsule on the tube. This groove and this rib seal the fillings of the tube with the capsule after tearing of the cover.

For the good drive in rotation of the cover by the capsule and the tearing of this cover, as well as for the precision of molding of the capsule, it is preferred to have a capsule material harder than the material of the head of the tube, typically: capsule made of high density polyethylene or polypropylene, in the case of a tube head made of low density polyethylene or linear low density polyethylene. The plastic material of the tube head is preferably identical to the plastic material forming the interior of the skirt of the tube, as already indicated. The less hard seal than the capsule is more easily retained there.

• utilisation du tube seul ou avec capsule, sans nécessité d'une dépression annulaire évasée entourant l'opercule, pour stocker et distribuer des liquides destinés à des soins oculaires ou cosmétiques;
• utilisation du tube avec une dépression évasée annulaire de formation des gouttes, pour stocker et distribuer goutte à goutte un vaccin liquide ou un liquide homéopathique.

Two important types of use should be reported:

• use of the tube alone or with capsule, without the need for a flared annular depression surrounding the cover, to store and distribute liquids intended for eye or cosmetic care;
• use of the tube with a flared annular depression for forming drops, for storing and dispensing drop by drop a liquid vaccine or a homeopathic liquid.

ADVANTAGES OF THE INVENTION

• The tight seal of the tube is both tearable and rigid, including at the level of its tear, which prevents it from bending during handling.
• the periphery of the base of the cover, in particular a drop-forming bowl, is thus not likely to be damaged by the manipulations
• the rigidity of the entire lid and its polygonal outline facilitate its grip despite its small dimensions
• this polygonal shape and its relatively large length facilitate its fitting into the key of the capsule and its retention, despite a slight clearance which also facilitates this fitting.

EXAMPLES

• Figure 1 shows a tube according to the invention provided with its cover, in axial section.
• FIG. 2 represents the cross section of the cover at the level of its future tear, in section AA perpendicular to the axis.
• Figure 3 shows a second tube according to the invention capped with its capsule, in axial section in its ½ left view, in axial section of the capsule, but not of the tube in its ½ right view.
• Figure 3a is an enlarged partial view.
• FIG. 4 represents the same tube, with the same ½ views, the inverted capsule fitting the cover.
• FIG. 5 represents the tube, with the same ½ views, and the capsule discarded after the rupture of the cover, the latter remaining trapped in the capsule which is cut axially.

Example 1

FIG. 1 represents a tube 1 whose head 2 made of low density polyethylene (LDPE) is overmolded on a skirt 3 having an internal layer 4 also made of LDPE. This head 2 is surmounted by a tearable lid 5 whose lateral external surface 6 is of essentially square contour (FIG. 2), having around its base 7 a slight annular hollow 8. The axial section of FIG. 1 shows two thick portions 9 and 9 ′ of the zone to be broken 40 of the cover, a zone lying on the one hand between the back arch 11 of the cover 5 and the circular axial internal surface 12 which connects with this arch at 13, and on the other hand, the foot from the outside of the cover 5 constituting the bottom 50 of the depression 8. The four portions such as 9 and 9 ′ of maximum thickness 0.4 mm are visible on the section AA of FIG. 2 passing through the bottom 50, they are alternated with four thin portions such as 14 and 14 ′ with a minimum thickness of 0.12 mm. The rupture by torsion of the cover 5 will be located according to a truncated cone 45 slightly inclined on the axis 16, going from the bottom of the hollow 8 in the vicinity of the circular connection 13 and corresponding to the minimum thicknesses 0.10 mm of the thin portions 14 and 14 ', as well as thick portions 9 and 9' whose maximum thickness is no more than 0.33 mm. The frustoconical rupture 15 is shown in FIG. 5. The square outline of the cover leaves around its base 7 enlargements 17 of the depression 8 (FIG. 2), so that the truncated cone 15 of the rupture has slight irregularities, without disadvantage on the flow of a contained liquid and on the formation of drops. In the general case, the cover can also be connected to the head of the tube without any annular depression around its base, the radius of this connection then typically being less than 0.5 mm.

Example 2

• opercule 5 de section droite carrée 2,5 x 2,5 mm avec de légers chanfreins aux angles, et de hauteur totale, mesurée à partir du fond 50 de la dépression annulaire 80, égale à 5 mm;
• dépression 80 de diamètre d'ouverture 3 mm et de profondeur 0,5 mm;
• portion d'orifice axiale cylindrique circulaire 12 de diamètre 1,5 mm, se raccordant en 13 à la voûte 11 haute de 1 mm;
• portions minces telles que 14 (figure 2) et portions épaisses alternées telles que 9 de la zone de déchirure ou zone à rompre 10, de mêmes épaisseurs à la hauteur du fond 50 de la dépression annulaire 80 (figure 3a) et selon la future déchirure 15 (figure 5) que dans le tube des figures 1 et 2;
• le goulot du tube est de diamètre 8 mm et sa jupe 3 est de diamètre 13 mm.

Figures 3 and 4 show a second tube also designated by 1, the only modification being the replacement of the slight hollow 8 (Figure 1) by an annular depression 80 whose frustoconical side surface 18 is 45 ° relative to the axis longitudinal 16, this surface 18 having to form with the rupture surface 15 of the cover (FIG. 5) a cup for forming drops 18 and 15.
The interesting dimensions of this tube 1 were as follows:

• cover 5 of square cross section 2.5 x 2.5 mm with slight chamfers at the corners, and of total height, measured from the bottom 50 of the annular depression 80, equal to 5 mm;
• depression 80 with an opening diameter of 3 mm and a depth of 0.5 mm;
• portion of circular cylindrical axial orifice 12 with a diameter of 1.5 mm, connecting at 13 to the arch 11 1 mm high;
• thin portions such as 14 (FIG. 2) and alternating thick portions such as 9 of the tear zone or zone to be broken 10, of the same thickness at the level of the bottom 50 of the annular depression 80 (FIG. 3a) and according to the future tear 15 (Figure 5) than in the tube of Figures 1 and 2;
• the neck of the tube is 8 mm in diameter and its skirt 3 is 13 mm in diameter.

FIG. 3 also shows the capsule 20 made of PP (polypropylene) screwed fully onto the tube 1. This capsule comprises a frustoconical cavity 21 which caps the contact 5 without any contact, and is bordered by a rib 22 which is inserted in position screwed into a peripheral annular groove 23 of the tube 1 encircling its annular depression 80, this depression acting beyond the open end 81 of the depression 80 (FIGS. 3 and 3a). This depression 80 and the cover are thus perfectly protected from shock or bruising while screwing on the capsule 20.

The capsule 20 also comprises, opening at its top, a hollow cavity 24 with a square section having a clearance of 0.08 mm over its width relative to the cover and a depth of 6 mm. This cavity 24 is surrounded by an outer cone 25, which fits into the annular depression 80 (Figure 4) when the capsule 20 fits the cover 5 to break it by rotation of this cover. This rupture is easily obtained whatever the direction of rotation of the capsule 20, the latter being conveniently held by two flat wings or ribs 26.

Figure 5 shows the tube 1 and the capsule 20 of Figures 3 and 4 after the rupture of the cover 5 which is now trapped in the hollow cavity or key 24 of the capsule 20. The orifice 12 and the formation bowl drops 15 and 18 now allow the delivery of calibrated drops and the capsule 20 allows the tube 1 to be filled after each dispensing.

INDUSTRIAL APPLICATION

Plastic tubes for storage and distribution of medical, paramedical or cosmetic liquids, in particular liquid vaccines to be dispensed in calibrated drops.

Claims (15)

1. Tube (1) made of plastics material having a head (2) topped by a tight cap (5) which may be torn by twisting, said cap having, down to its base (7) connected to said head (2), a lateral surface (6) of polygonal contour, this surface being formed by generatrices inclined at less than 10° to the axis (16) of the tube (1), said cap (5) having a tear zone (10) contained between said lateral surface (6) and an internal surface (11) having successive circular sections perpendicularly to said axis, these surfaces (6 and 11) together defining at least one thin portion (14, 14'), characterised in that said at least one thin portion has a minimum thickness of between 0.05 and 0.18 mm and in that said lateral and internal surfaces (6 and 11) together define at least one thick portion (9, 9') having a maximum thickness at least 1.5 times greater than said minimum thickness.
2. Tube (1) according to claim 1, in which said head (2) is moulded onto the skirt (3), the plastics material of the head (2) being identical to the plastics material forming the internal surface (4) of said skirt (3), this plastics material being either low density polyethylene having a density of between 0.88 and 0.93 g/cm³ or low density linear polyethylene.
3. Tube (1) according to claim 1, in which said tear zone (10) comprises at least two said thin portions (14 and 14') alternating with said thick portions (9 and 9'), the maximum thickness of each thick portion (9) being 2.5 to 4 times greater than the minimum thickness of each thin portion (14).
4. Tube according to any one of claims 1 or 3, in which said base (7) of the cap (5) is connected to said head (2) in a flared annular depression (8, 80) of said head (2), the diameter of the emergent end (81) of said depression being less than 2 mm greater than the external width of the base (7) of the cap (5) and said cap (5) exceeding this depression (8; 80) by a height at least equal to said diameter.
5. Tube (1) according to claim 4, in which the diameter of the emergent end (81) of said depression (80) is between 2.5 and 7 mm, the external width of the base (7) of the cap (5) being between 2 and 6 mm.
6. Tube (1) according to any one of claims 1 to 5, in which said internal surface (11) of the cap (5) belongs to an arch (11) forming the reverse of said cap (5), said arch (11) having a height of less than 1.3 mm and being connected to a circular cylindrical axial internal surface (12) forming part of the orifice (12 and 15 and 18) of the tube (1) after tearing of the cap (5).
7. Tube (1) according to claim 4, in which said flared annular depression (80) of said head (2) has a truncated cone shaped lateral surface (18), the surface (18) being extended by the breakage surface (15) of the cap (5) and forming with it a droplet formation surface (15 and 18) dominating and being connected to a circular cylindrical axial internal surface (12) of the head (2) of the tube (1), said extended truncated cone shaped surface (18 and 15) and said axial internal surface (12) allowing the expulsion of metered liquid droplets.
8. Tube (1) according to any one of claims 1 to 3, accompanied by or equipped with a cover (20) which is detachably fixed on the tube (1), this cover (20) covering the cap (5) of the tube (1) without making contact with it and comprising a hollow cavity opening at its top and constituting a key (24) allowing said cap (5) to be surrounded, producing a surface for the driving of the cap (5) by the cover (20) having a height which is at least twice the external width of the base of the cap (5) and an inclination to the axis of less than 10°, when the cover (20) is removed and inverted, and allowing this cap (5) to be broken by rotation of the cover (20).
9. Tube (1) accompanied by a cover (20) according to claim 8 in which said generatrices of the external lateral surface (6) of the cap (5) are inclined at less than 5° to the longitudinal axis (16), said key (24) of the cover (20) fitting fully over said cap (5) by merely being driven home.
10. Tube accompanied by a cover (20) according to claim 9, in which said generatrices are inclined at most at 2° to the axis (16), said key (24) fitting fully over said cap (5) and holding it there after the breakage thereof.
11. Tube (1) accompanied by a cover (20) according to any one of claims 8 to 10, in which said base (7) of the cap (5) is connected to the head (2) of the tube (1) in a flared annular depression (80) having a truncated cone shaped lateral surface (18) of said head (2) of the tube (1) and in which said cover (20) comprises, at its top, a terminal external cone (25) surrounding its hollow cavity (24), said cone (25) fitting in said annular depression (80) when the cover (20) fits on said cap (5).
12. Tube (1) accompanied by a cover (20) according to claim 11, in which the head (2) of the tube (1) comprises a peripheral annular groove (23) surrounding its annular depression (80), the cover (20) being fixed on the tube (1) and comprising an annular internal rib (22) which engages fully in said peripheral annular groove (23) for fixing the cover (20).
13. Tube (1) accompanied by a cover (20) according to any one of claims 8 to 12, the head (2) of the tube (1) being of low density polyethylene or of low density linear polyethylene and the cover (20) being of high density polyethylene or of polypropylene.
14. Use of the tube (1) according to any one of claims 1 to 3 or 8 to 10 for storing and dispensing liquids intended for ocular or cosmetic purposes.
15. Use of the tube (1) according to any one of claims 7, 11 or 12 for storing and dispensing, dropwise, a liquid vaccine or a homeopathic liquid.

Images