Cap made of foamed polymeric material, and method of making same

Abstract

A cap for a bottle, which comprises at least a sealing portion and a lateral portion for fastening to the bottle. The sealing portion comprises, along a direction substantially perpendicular to the lateral portion, a first region formed of unfoamed polymeric material, a second region formed of foamed polymeric material, and a third region formed of unfoamed polymeric material, the second region being positioned between the first region and the third region. The disclosure also relates to a process for manufacturing a cap made of foamed polymeric material.

Claims

1. A flip-top dispensing closure comprising a base and a lid joined by a hinge, the base including a top deck with a dispensing orifice; and the lid comprising a top plate, wherein the top deck and/or the top plate comprise a layer of foamed polymeric material sandwiched between two layers of unfoamed polymeric material, wherein the hinge is formed from unfoamed polymeric material; and in which the top deck and the top plate both have a foamed core sandwiched between two non-foamed layers.

2. The closure of claim 1, in which the closure is obtained from a formulation comprising at least one propylene-based polyolefin and at least one blowing agent in a proportion of active components of between 0.3% and 2.5% by weight.

3. The closure of claim 1, in which the material of the top deck and/or top plate comprises an expansion ratio of between 30% and 70%.

4. The closure of claim 1, in which the closure is obtained from a formulation having a melt flow index of between 20 and 50 (g/10 min).

5. The closure of claim 1, in which the closure is obtained from a process for manufacturing a closure, the process comprising: (a) providing a plastics formulation comprising at least one blowing agent; (b) providing an injection mould; (c) arranging the mould so as to create a first gap; (d) injecting the formulation into the injection mould so as to substantially fill the first gap; and (e) moving the mould so as to form a second gap greater than the first gap so that the blowing agent generates expansion of the formulation until substantially the whole of the second gap is filled whereby to selectively foam part of the closure; in which the closure includes a base with a top deck and a lid with the top plate, the base and lid being joined by a hinge and in which the hinge has a thin thickness such that it is very quickly cooled and solidified before the mould is opened for foaming.

6. The closure of claim 5, wherein the process for manufacturing the closure comprises: (f) providing at step (a) a formulation comprising at least one propylene-based polyolefin and at least one blowing agent in a proportion of active components of between 0.3% and 2.5% by weight; (g) providing at step (b) an injection mould comprising a fixed part and a mobile part; (h) at step (c) positioning the mobile part over the fixed part so as to create a first gap; (i) at step (d) injecting the formulation into the injection mould so as to fill the first gap; and (j) at step (e) moving the mobile part of the injection mould in an opening direction with respect to the fixed part of the injection mould so as to form a second gap greater than the first gap so that the blowing agent generates the expansion of the formulation in a direction perpendicular to the opening direction of the injection mould until the whole of the second gap is filled.

7. The closure of claim 6, in which the ratio between the second gap and the first gap is between 1.2 and 1.8.

8. The closure of claim 5, in which formulation has a melt flow index of between 20 and 50 (g/10 min).

9. A process for manufacturing the cap of claim 1 which comprises the steps of: (i) providing a formulation which comprises at least one blowing agent; (ii) providing an injection mold which includes a fixed part and a mobile part; (iii) positioning the mobile part over the fixed part so as to create a first gap; (iv) infecting the formulation into the injection mold so as to fill the first gap; and (v) moving the mobile part of the injection mold in an opening direction with respect to the fixed part of the injection mold so as to form a second gap greater than the first gap so that the blowing agent generates the expansion of the formulation in a direction generally perpendicular to the opening direction of the injection mold until the whole of the second gap is filled.

10. The process set forth in claim 9, wherein the ratio between the second gap and the first gap is between about 1.2 and about 1.8.

11. The process set forth in claim 10, wherein the cap includes a base with a top deck and a lid with the top plate, the base and lid being joined by a hinge, and wherein movement of the mold to form the gap expands a cavity of the mold in a region of the base top deck and the lid top plate and not in the region of the hinge.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A specific, illustrative, representative bottle cap, according to the disclosure, is described below with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a cap, according to one embodiment of the disclosure, before blowing of a formulation of polymeric material;

(3) FIG. 2 illustrates the cap of FIG. 1 after blowing of the formulation of polymeric material;

(4) FIG. 3 represents a cap in accordance with another embodiment of the disclosure;

(5) FIG. 4A illustrates a cap according to a further embodiment of the disclosure;

(6) FIG. 4B is a sectional view of the cap taken along line A-A of FIG. 4A;

(7) FIG. 5 illustrates a first step of a process for manufacturing a cap, according to one embodiment of the disclosure;

(8) FIG. 6 shows a second step of the process set referenced in FIG. 5;

(9) FIG. 7 illustrates a first step of a process for manufacturing a cap, according to an alternative embodiment of the disclosure; and

(10) FIG. 8 shows a second step of the process referenced by FIG. 7.

(11) The same numerals are used throughout the drawing figures to designate similar elements. Still other objects and advantages of the disclosure will become apparent from the following description of specific, illustrative embodiments.

DETAILED DESCRIPTION

(12) Example or representative embodiments are described below in sufficient detail to enable those of ordinary skill in the art to embody and implement the articles, systems and processes described. Such embodiments can be provided in many alternate forms and should not be construed as limited to the particular examples set forth herein.

(13) Accordingly, while embodiments can be modified in various ways and take on various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below as examples. There is no intent to limit to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included. Elements of the example embodiments are consistently denoted by the same reference numerals throughout the drawings and detailed description where appropriate.

(14) The terminology used herein to describe embodiments is not intended to limit the scope. The articles a, an, and the are singular in that they have a single referent, however the use of the singular form in the present document should not preclude the presence of more than one referent. In other words, elements referred to in the singular can number one or more, unless the context clearly indicates otherwise. It will be further understood that the terms comprises, comprising, includes, and/or including, when used herein, specify the presence of stated features, items, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, items, steps, operations, elements, components, and/or groups thereof.

(15) Unless otherwise defined, all terms (including technical and scientific terms) used herein are to be interpreted as is customary in the art. It will be further understood that terms in common usage should also be interpreted as is customary in the relevant art and not in an idealized or overly formal sense unless expressly so defined herein.

(16) FIG. 1 illustrates the shape of a precursor 1 of a cap according to the invention before blowing of the formulation of the plastic material and FIG. 2 illustrates the cap 100 for a bottle intended to contain a fluid, after blowing of the plastic material. The cap 100 comprises a sealing portion 2, having the general shape of a disc intended to seal a bottle, and a lateral portion 6 comprising a screw thread for fastening to the bottle. The lateral portion 6 has a cylindrical general shape solidly attached to the sealing portion 2. After blowing as illustrated in FIG. 2, the sealing portion 2 of the cap 100 has three regions that extend in a plane parallel to the plane of the disc a first region 3 made of unfoamed plastic material, commonly referred to as the skin, a second region 4 made of foamed plastic material commonly referred to as the foamed core and a third region 5 made of unfoamed plastic material or skin. The expansion ratio of the plastic material of the sealing portion 2 is around 50% so that it has a thickness of around 1.5 mm. This thickness and this expansion ratio make it possible to achieve mechanical properties similar to those of a conventional sealing portion 2. The lateral portion 6 is made of unfoamed plastic material, it has a thickness of around 1 mm.

(17) According to one variant of the cap 100 that is not illustrated, the sealing portion 2 and the lateral portion 6 have other shapes. In another variant, the lateral portion 6 is devoid of a screw thread but comprises any other type of device for fastening to the bottle.

(18) According to one variant that is not illustrated, the expansion ratio is between 20% and 80%. According to yet another variant, the expansion ratio is between 30% and 70%.

(19) FIG. 3 illustrates a cap 100 according to a second embodiment of the invention. This cap 100 differs in particular from the cap 100 from the first embodiment in that it comprises an orifice 7 for the passage of a fluid and a closure portion 9 for closing the orifice 7, connected to the sealing portion 2 via a hinge portion 8. The sealing portion 2 and the closure portion 9 are formed of at least one foamed plastic material with an expansion ratio of 70%. The thicknesses of said portions 2, 9 are around 1.7 mm. Furthermore, the hinge portion 8 made of plastic material has a thickness of around 0.7 mm of unfoamed plastic material. Indeed, this thin thickness is very quickly cooled after injection of the formulation, so that when the mould is opened for the foaming, this portion 8 is already solidified. The lateral portion 6 is made of unfoamed material for the same reasons as those mentioned above.

(20) According to one variant that is not illustrated, the cap 100 is devoid of the hinge portion 8 so that the closure portion 9 is not connected to the cap 100.

(21) FIG. 4A illustrates a cap 100 according to a third embodiment which differs from the preceding two in that the face of the sealing portion 2 located on the side of the lateral portion 6 is equipped with a reinforcing element 11 that has the shape of a rib made of unfoamed plastic material that increases the mechanical strength of the sealing portion 2. FIG. 4B illustrates the same embodiment along a cross-sectional view along the axis A-A. According to other possibilities that are not illustrated, the rib 11 may be curvilinear, may have several concentric circles, form a cross and any other shape that makes it possible to reinforce the sealing portion 2. According to yet another possibility that is not illustrated, the rib 11 is provided on the closure portion 9 of a cap 100.

(22) The cap 100 illustrated in FIGS. 1 to 4 is obtained from a formulation comprising at least one propylene-based polyolefin and at least one blowing agent in a proportion of active components of between 0.3% and 2.5% by weight and a melt flow index of between 20 and 50 g/10 min. According to another variant, the polyolefin comprises a copolymer of propylene and ethylene PP, a homopolymer, a statistical copolymer or a mixture of these materials.

(23) FIGS. 5 and 6 illustrate the process for manufacturing a cap 100 according to one embodiment of the invention.

(24) FIG. 5 illustrates an injection mould 200 comprising a fixed part 12 and a mobile part 13 that are positioned with respect to one another so as to form a first gap 14. The formulation comprising a blowing agent is injected until the space formed by the first gap 14 is filled. The thinnest portions, such as the hinge portion 8 for example, cool very rapidly so that the plastic material solidifies. Then, as illustrated in FIG. 6, the mobile part 13 of the mould is moved with respect to the fixed part 12 so as to open the mould 200 by forming a second gap 15 larger than the first gap 14. The formulation then foams in a direction parallel to the opening direction (arrow 16) of the mould. Thus, the portions oriented in a direction substantially perpendicular to the opening direction 16 of the mould may foam until the whole of the space delimited by the second gap 15 is filled. Therefore, the sealing portion 2 of the cap 100 has at least one region 4 made of foamed plastic material between two skins 3, 5 and the lateral portion 6 has a plastic material that is not foamed due to lack of space.

(25) The difference between the first gap 14 and the second gap 15 is determined by the desired expansion ratio. The second gap 15 is between 1.2 and 1.8 times the first gap 14.

(26) Thus, the present invention proposes a light cap 100 that requires less raw material than a conventional cap while having the same properties. Furthermore, the invention also proposes a process for the manufacture of such caps which is simple and rapid to implement.

(27) FIGS. 7 and 8 illustrate an alternative moulding process.

(28) FIG. 7 shows a first moulding phase in which a foamable plastics material is injected into a mould cavity to form an intermediate piece 115.

(29) Thereafter an internal movement within the mould forms an enlarged cavity for a second moulding phase shown in FIG. 8 in which the material foams to fill the cavity to form the final piece 100.

(30) In this embodiment the piece 100 is a flip-top dispensing closure with a base 120 and a lid 121 joined by a hinge 122. The base 120 includes a generally disc-shape, circular top deck 123 with a dispensing orifice 124 and a generally cylindrical sidewall 125 depending from the periphery of the deck 123. The lid 121 includes a disc-shape, generally circular top plate 126 with a generally cylindrical truncated sidewall 127 depending from the periphery thereof.

(31) In this embodiment the movement of the mould expands the cavity in the region of the base top deck 123 and the lid top plate 126 to form a foamed core 123b, 126b sandwiched between two non-foamed layers 123a, 123c, 126a, 126c.

(32) It goes without saying that the invention is not limited to the embodiment described above by way of example, but that it comprises all the technical equivalents and variants of the means described and also combinations thereof.

(33) Although specific, illustrative embodiments have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiments shown and that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.