EP0693434B1 - Screw cap with liner - Google Patents

Abstract

A stopper for the threaded neck of a receptacle comprises: (a) a base surface (5), and (b) an annular skirt (6) projecting from the base and with an internal thread, and with: (c) a hermetic circular joint (4) of dia. greater than the exterior dia. of the neck of the receptacle, fixed in the body of the capsule adjacent to the base. The body of the capsule has means for tightening the joint against the outer face and the exterior edge of the neck, formed by an interior rim at the intersection of the skirt and the base of the capsule body. The joint (4) is formed by, or contains, a plastic material with high modulus of rigidity, as a barrier against gas, and the rim (9) defines, within the body of the capsule, at a height greater than the thickness of the joint (4), a truncated cone with an angle at the top not greater than 90 degrees C, and fitting together by a concave part (12) with the base (5), and by a concave part (13) with the skirt (6). <IMAGE>

Description

The present invention relates to a capsule for the plugging the threaded neck of a container such as a bottle, composed a capsule body comprising a bottom wall, and a skirt annular projecting from the bottom wall and having a thread inside, and a circular gasket of outside diameter greater than the outside diameter of the neck, reported in the body of capsule in a position adjacent to the bottom wall, the body of capsule being provided with means for tightening the seal against the face end and against the outer edge of the container neck.

Capsules of this type are known, for example, from EP-A-055 916 and US Patent No. 4,658,976.

According to request EP-A-055 916, a flange or bead ring is provided inside the capsule body, at the intersection of the bottom wall with the skirt. In FIG. 3, this rim presents the shaped like a rectangular bleacher with a substantially vertical side aligned with the outside surface of the neck, a horizontal flank and a convex part connecting these two sides together. According to Figure 6, the rim may have the shape of a convex bead without sides horizontal and vertical, generally more or less frustoconical, this bead connecting to the skirt perpendicular to the axis of the capsule body and connecting to the back wall at an angle of about 45 ° by concave rounding, respectively. According to Figure 7, the rim is a simple concave bead, i.e. a rounded the angle of intersection of the bottom wall with the skirt of the body of capsule. It should be noted that in all of the embodiments, a retaining ring is provided on the skirt to hold the seal in position.

According to US-A-4 658 976, an annular step also having a vertical side and a horizontal side is provided at the intersection of the bottom wall with the skirt of the capsule body. However, the vertical side of this step here is not aligned with the outside of the neck of the container, but offset towards the outside by compared to this face by a distance much less than the thickness of the seal, so as to obtain, when the capsule is tightened on the neck, bending of the outer part of the joint and tightening of this part of the seal against the outside face of the neck, with a compression of this part corresponding to a reduction of the thickness of the joint between 40 and 60%.

These known capsules have given satisfactory results when used with seals made of soft and flexible material, for example in ethylene-vinyl acetate (EVA) copolymer. However, the use of such seals on bodies of capsules produced made of plastics such as polypropylene the disadvantage that both the materials used for the realization joints that the materials used to make the bodies of capsules are relatively permeable to gases such as oxygen, carbon dioxide, nitrogen. Therefore, the lifespan of the products packaged in bottles, flasks or other closed containers by such capsules is reduced due to gas exchange at through the capsules.

These gas exchanges can for example lead to a penetration of oxygen inside the containers, resulting in spoilage organoleptic properties of sensitive products such as bodies unsaturated fat. They can also cause loss aroma of aromatic substances. These gas exchanges can by elsewhere cause uptake, by the product contained in the container, unwanted external odors related for example to the product storage environment. This is the reason it has already been proposed to use, for these applications, seals having better barrier properties to gases and other substances volatile. Such seals include at least one layer in one gas barrier plastic, high modulus stiffness, possibly combined with at least one layer in one plastic material with low modulus of rigidity. For example, the layer with high modulus of rigidity, gas barrier effect, can be consisting of PET (poly (ethylene terephthalate)), PA (polyamide), PVDC poly (vinylidene chloride) or E / VAL (ethylene / alcohol vinyl)), having a stiffness modulus of the order of 1300 to 2200 MPa.

However, it turned out that the use of seals of this type in capsules according to the aforementioned prior documents did not give satisfaction, these rigid joints having, unlike flexible joints and flexible normally used in these capsules, tend not to follow the shape of the annular tightening rim, so do not sufficiently surround the lateral part of the neck and even place in the capsule body in an oblique position relative to at the bottleneck. In all cases, this results in reduced tightness, or even random.

The present invention relates to a screw closure cap combining good sealing performance and good gas impermeability, thanks to the use of a gasket high-modulus gas barrier plastic stiffness, or comprising at least one layer of such a material.

The capsule object of the invention for plugging the neck threaded container is composed of a capsule body and a seal circular seal fitted in the capsule body. The body of capsule includes a bottom wall, and an annular skirt making projection on the bottom wall and having an internal thread. Gasket seal has an outer diameter greater than the diameter outside of the stopper container neck. The capsule body is provided with means for tightening the seal against the end face and against the outer edge of the neck. Said means include a rim annular of general frustoconical shape provided inside the capsule body, at the intersection of the bottom wall with skirt, and connecting by a concave part to the bottom wall and by a concave part to the skirt. According to the invention, the seal is made up of or comprises a plastic material with a gas bournière effect, having a stiffness modulus between about 1300 and 2200 MPa, and the shape general frusto-conical edge extends over a height greater than the thickness of the attached and present an apex angle of 90 ° or less.

Thanks to this conformation of the rim, the joint relatively rigid can nevertheless deform to follow the shape of the edge and thus be tightened all around the edge against the edge outside of the neck and seal at the location of said edge, even when the latter presents irregularities, this for a relatively low compression of the joint.

Preferably, said rim extends over a height equal to at minus twice the thickness of the joint.

The angle at the top of the general frustoconical shape of the rim can advantageously be between 90 and 45 ° and be preferably around 60 °.

This general frustoconical shape can, according to a mode of preferred embodiment of the invention, be defined by two parts frustoconical, one of which forms an angle at the apex between 45 and 60 ° and is connected by a concave part to the bottom wall of the body capsule and the other makes an angle at the top between 60 and 90 ° and is connects by a concave part to the skirt of the capsule body, the two frustoconical parts connecting to each other by a part convex.

la figure 1 est une coupe axiale d'une capsule conforme à l'invention avant serrage du joint d'étanchéité;

la figure 2 est une coupe de la capsule de la figure 1, après serrage du joint d'étanchéité par vissage de la capsule sur un goulot.

Referring to the appended schematic drawings, there will be described below in more detail an illustrative and nonlimiting embodiment of a closure cap according to the invention; on the drawings:

Figure 1 is an axial section of a capsule according to the invention before tightening the seal;

Figure 2 is a section of the capsule of Figure 1, after tightening the seal by screwing the capsule on a neck.

The screw cap 1 as illustrated in FIG. 1 is drawn at the stopper of the neck 2 of a bottle containing by example a carbonated drink.

Capsule 1 consists of a capsule body 3 and a seal sealing 4 reported.

The capsule body 3 comprises a bottom wall 5 and a annular skirt 6 projecting from the bottom wall 5. The wall 6 is internally provided with a thread 7 capable of cooperating with a external thread 8 of the neck 2, when the capsule 1 is screwed onto the neck 2.

The capsule body 3 internally has a rim 9 to the location of the intersection of the skirt 6 with the bottom wall 5.

The inner rim 9 defines a generally frustoconical shape with a vertex angle less than 90 °, in this case of the order of 60 °. This general frustoconical shape is defined by two parts frustoconical 10 and 11, the first of which forms an angle at the top about 45 ° and the second an apex angle of about 90 °, the part 10 connecting to the bottom wall 5 by a concave part 12 and the part 11 connecting to the skirt 6 by a concave part 13. The two parts 10 and 11 are connected to each other by a part convex 14.

It should be noted that the height of the rim 9 is greater than the thickness of the joint 4. In the example shown, the height of the flange 9 is approximately equal to four times the thickness of the joint 4.

The seal 4 has a substantially equal outside diameter the inside diameter of the skirt 6 in the part located above the thread 7. The seal 4 attached in the capsule body 3, between the thread 7 and the bottom wall 5 is intended to seal the neck 2 when the capsule 1 is screwed onto the latter.

As shown in Figure 2, this seal must be produced on the one hand by tightening the seal 4 between the end face 15 the neck 2 and the bottom wall 5 of the capsule body 3 and on the other hand, by tightening the seal 4 between the outer edge 16 of the neck 2 and the inner rim 9 of the capsule body 3. The seal 14, even if it is rigid, can follow the shape of the rim, by bending at less than 90 °, in the occurrence at approximately 60 °, and undergoes only reduced compression.

Although the capsule as described above can be used in combination with 4 attached seals of all types, including including soft and flexible seals such as ethylene acetate copolymer vinyl or polyvinyl chloride, it has special advantages in combination with rigid seals, designed specially to ensure good gas impermeability. he can these are, for example, composite joints comprising at least one layer having a high modulus of rigidity, possibly combined with one or more layers with low modulus of rigidity. Such a seal composite can for example include a middle layer consisting of a sheet of PET, PA, PVDC or E / VAL of a thickness between 100 and 250µm, having a stiffness modulus between approximately 1300 and 2200 MPa, and at least two layers external each made of a sheet of PP elastomer of a thickness between 300 and 550µm, presenting a module of stiffness between about 100 and 300 MPa. Such a composite joint optimally combines gas impermeability properties, thanks to the barrier effect of the high modulus middle layer of stiffness, and liquid tightness properties, thanks to the layers exterior with low stiffness modulus.

A capsule combining a polypropylene capsule body and such a rigid composite joint can find applications particularly advantageous for corking bottles containing carbonated drinks.

In particular when using such a rigid joint 4, it can be advantageous, in order to prevent any lateral displacement of the seal, provide on the bottom wall 5 of the capsule body 3, on the face bottom of this wall, preferably above the face end 15 of the neck 2 of the locking means which can be present for example in the form of an annular rib 17 continuous or discontinuous, of variable profile, preferably in V, with acute or rounded apex angle. The height of these blocking means can be, for example, between approximately 0.1 and 0.3 mm for a seal of the type as described above by way of example. These means of blocking sink into the seal 4, when tightening the capsule, as shown in figure 2.

Claims (10)

1. Cap (1) for the screwthreaded neck (2) of a container, comprising a cap body (3) having an end wall (5) and an annular skirt (6) projecting from the end wall and having an interior screwthread (7), and a circular seal (4) having a diameter greater than the outside diameter of the neck of the container inserted into the cap body in a position adjacent the end wall, the cap body having means for clamping the seal against the end face and against the outside edge of the neck in the form of an interior bead (9) where the skirt and the end wall of the cap body intersect having a frustoconical overall shape and merging through a concave part (12) with the end wall (5) and through a concave part (13) with the skirt (6), characterised in that the seal (4) is made of or incorporates a gas barrier plastics material having a stiffness between about 1 300 MPa and about 2 200 MPa and the frustoconical overall shape extends over a height greater than the thickness of the seal (4) and has a cone angle equal to or less than 90°.
2. Cap according to claim 1 characterised in that said frustoconical shape extends over a height equal to at least twice the thickness of the seal (4).
3. Cap according to claim 1 or claim 2 characterised in that the cone angle of said frustoconical shape is between 90° and 45°.
4. Cap according to any one of the preceding claims characterised in that the cone angle of said frustoconical shape is in the order of 60°.
5. Cap according to any one of the preceding claims characterised in that said frustoconical overall shape is defined by two frustoconical parts (10, 11) the first of which has a cone angle between 45° and 60° and the second of which has a cone angle between 60° and 90°, said two frustoconical parts (10, 11) merging through a convex part (14).
6. Cap according to any one of the preceding claims characterised in that the cap body (3) has on the inside face of the end wall (5), above the end face (15) of the neck (2), projecting locating means (17) which are impressed into the seal (4) when the cap is screwed down.
7. Cap according to claim 1 characterised in that the seal (4) comprises at least one layer between 100 µm and 250 µm thick of said plastics material having a stiffness between about 1 300 MPa and about 2 200 MPa.
8. Cap according to claim 7 characterised in that said layer is a PET, PA, PVDC or E/VAL film.
9. Cap according to claim 7 or claim 8 characterised in that the seal (4) further comprises at least one layer between 300 µm and 550 µm thick of a plastics material having a stiffness between about 100 MPa and about 300 MPa.
10. Cap according to claim 9 characterised in that said layer is a PP elastomer film.

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