WO2017158209A1 - Tubular container with an outer tube and an inner container - Google Patents

Abstract

The invention relates to a tubular container (1) made from flexible material, comprising an outer tube (10) and an inner container (30) housed inside the outer tube (10) and intended to come into contact with the product (51) in the container. A flexible shoulder (32) of the inner container (30) is secured to a head (12) of the outer tube (10), with an intermediate cavity (7) being formed between the outer tube (10) and the inner container (30). At least one hole (24) connects the intermediate cavity (7) with the exterior of the tubular container (1). The head (12) can include an airless or one-way valve. The outer tube (10) can recover its shape while the inner container (30) remains compressed during the use of the tubular container (1). The outer tube (10) and the inner container (30) are preferably made from materials that meet different requirements. The distal end (36) of the inner container (30) is preferably flared against the outer tube (10).

Description

 TUBULAR CONTAINER WITH AN OUTER TUBE AND A CONTAINER

INSIDE

DESCRIPTION

Technical sector

The invention relates to a tubular container of flexible material for housing a cosmetic, food, medicament or the like, and in particular to a tubular container that includes an outer tube and an inner container housed within the outer tube.

State of the art

In the cosmetics, pharmacy or food sectors, the use of plastic flexible tubes is widespread. Plastic flexible tubes are characterized by comprising a hollow body or skirt, intended to contain a product (for example, a cosmetic cream), and a head arranged at one end of the skirt and intended to allow the product to be evicted or dosed. The head may be provided with a product outlet neck, a cap, metering mechanisms, etc. Once the tube is filled with a product, the end of the skirt opposite the head is sealed by heat transfer welding, usually by hot air, hot jaw, ultrasound, etc.

Said plastic flexible tubes are obtained from various manufacturing methods such as extrusion, coextrusion, mold injection, etc. Also, various methods are known to provide flexible plastic tubes with any informative or decorative element, by including texts, graphics, drawings, etc. either directly on them or by incorporating another element, such as a label. For example, flexible plastic tubes can be decorated by techniques such as offset, flexography, screen printing, stamping (in English, "stamping"), self-adhesive labels, etc. Also, in pipe manufacturing processes by Injection in mold, the technique known as Mold Labeling or, in English, Ίη-Mold Labeling "(IML), to provide tubes with a label is very common. Despite its extensive implementation in the market, the manufacture of Plastic flexible tubes presents certain problems still unsolved.

For example, a first problem consists in the difficulty of selecting the tube manufacturing materials, in particular in the mold injection processes. The materials used must have very special characteristics and meet requirements such as being able to be processed, have adequate weldability, impermeability, resistance to cracking when the material is under tension (ESCR), etc. In the field of food, materials must also meet strict requirements related to safety in food contact, since the tubes on the market must be in direct contact with the product packaged inside. In the field of cosmetics, food and pharmacology, materials must meet specific fitness and suitability requirements, such as non-toxicity, global and specific migrations, etc., since the tubes must be in direct contact often with products ingestible or applicable in the body. Normally, these characteristics and the fulfillment of requirements are achieved through the selection and use of mixtures of polymers and other components, especially in the case of tubes manufactured by injection in mold. However, obtaining polymer mixtures that meet such a variety of requirements, including mechanical requirements, food contact, non-toxicity, processability, etc. It is extremely complex and expensive. To this we must add that, when polymer mixtures are used, it is difficult to maintain and guarantee the properties of the mixture due to the tolerance in the fundamental variables (fluidity, density, stiffness, etc.) of the polymers included in the mixture. Therefore, it is extremely complex to obtain a polymeric mixture that has all the necessary properties balanced in order to successfully manufacture and use a tube, and in particular an injected tube. On the other hand, the obligation to achieve polymer mixtures that meet strict food contact requirements or non-toxicity directly prevents a significant number of polymers from being used in the preparation of the mixtures. This makes the design of polymer blends more difficult.

A second problem has to do with a type of tube known in the state of the art actually formed by two tubes, one inside the other. The solution of arranging a tube inside another is usually used to obtain an "airless" container, that is, a container that prevents the entry of air into the container in order to improve the preservation of the packaged product (for example products such as creams without additives, serums, vitamin C, etc.). This solution is also often used to resolve the collapse effect with use. In this type of tubular packaging, both the inner tube and the outer tube are provided with a skirt and a head provided with an outlet neck. The inner and outer tubes are joined by their exit necks. This solution has deficiencies in obtaining a high rate of return (ability to deliver the entire contents of the tube), since the tube cannot completely collapse due to the high stiffness of the inner tube head.

A third problem has to do with the sealing of double tube tubular containers, such as those mentioned in the previous paragraph or as bi-product containers (tubular containers formed by an inner tube and an outer tube and containing two different products, where The outer tube has a special configuration head with two exit holes of the two products, so that the two products go outside in unison and mix together at the exact moment of their application). For the assembly of the aforementioned double tube containers it is required that the skirt of the inner tube and the skirt of the outer tube have a substantial diameter difference, in order to be able to effectively assemble the inner tube inside the outer tube. This causes that, when the end of the skirts is flattened for joint sealing, there is no intimate union between the skirts of the two tubes, internal and external, causing failures in the sealing. Specifically, in the central zone the seal has four wall thicknesses, while on the sides there are only two. When compressing the jaws that make the walls weld the pressure is correct in the area of four walls but insufficient in the area of two, producing a bad soldier in that area. Also this clearance makes it difficult to introduce the welding nozzle, which must be adjusted inside the tube with great precision.

The present invention aims to provide a new tubular container design that solves at least one of the above problems.

Brief Description of the Invention

The object of the invention is a tubular container of flexible material for housing a cosmetic, food, medicament or the like, and a method of manufacturing said tubular container of flexible material. The tubular container comprises an outer tube and an inner container. The outer tube comprises a skirt and a head, where the head generally includes, among others, a neck, a thread, etc. The inner container, in turn, is provided with a skirt and, in preferred embodiments of the invention, a shoulder at a proximal end of the skirt. The shoulder is an open lid, that is, it has a hole and therefore does not completely close said proximal end of the inner container skirt. Said shoulder is flexible or deformable, preferably presenting a plastic deformation. The inner container is housed inside the outer tube, and the shoulder of the inner container is preferably fixed tightly inside the head of the outer tube, so that the shoulder of the inner container can seal the inner container once the end is sealed proximal tubular container. The inner container, therefore, does not have a typical tube head typical of conventional flexible tubes (with neck, thread, etc.), but when welded with the outer tube it takes advantage of the neck, thread, etc. of the head of the outer tube to be able to dislodge its contents. In other words, the inner container shares or appropriates the use of the neck of the outer tube head. Moreover, the present shoulder preferably It has a high deformability without compromising the welding of the shoulder to the head of the inner container. In addition, the shoulder is preferably made from a laminated complex (aluminum or other) equal to or similar to the skirt of the inner container, presenting advantages in cost and a very high deformability (this being a plastic type deformation and therefore avoiding the recovery of the form and ensuring the permanent collapse of the inner container). A gap is defined between the inner container and the outer tube. Preferably, the tubular container is able to recover its original shape after proceeding with its use, that is, after pressing the tubular container to extract the product contained therein. In contrast, the inner container is preferably deformed by a unidirectional non-return valve that prevents the return of air into the inner container; preferably, said unidirectional non-return valve is arranged in the head of the outer tube, in a cap fixed to the head of the outer tube or in another part such as an applicator or a pump. Additionally, the distal end of the inner container is preferably deformed and widened (or flared) so that it is attached to the distal end of the outer tube. The outer tube and the inner container may be made of different materials, so that the inner container, intended to be in contact with the packaged product, satisfies requirements related to said function while the outer tube, which is visible outside, does not it must satisfy these requirements of the inner container and instead satisfy requirements related to its function such as carrying one or more decorative elements, labels, etc.

A first advantage, offered by at least some embodiments of the invention and in particular by those embodiments in which the materials of the outer tube and the inner container meet different requirements, is that the selection of materials is facilitated. This solves one of the main problems of the injected tubes and to some extent of the extrudates and of the rest of tube manufacturing techniques, which require the use of materials with high requirements and performance. For example, the possibility of using recycled materials is opened, in particular to manufacture the outer tube, guaranteeing that said recycled materials do not come into contact with the packaged product and that the tubular container therefore complies with current regulations related to the packaging of the food, pharmacy or cosmetics sector.

An additional advantage, offered by at least some embodiments of the invention, is that it is possible to reduce the thickness of the outer tube compared for example with a traditional injected tube that does not contemplate the present double tube version, since in the In this invention, the outer tube has a purely mechanical function and must not be in contact with the packaged product. This reduction in thickness would not be possible if the product were in contact with the outer container as permeability would be affected. Having a smaller wall thickness the container would be more permeable and therefore would not conveniently protect the product to be contained, and its characteristics may vary by permeating part of its components. The impermeability property necessary in the tubular container of the present invention, on the other hand, is provided by the inner container, which may be made of laminated materials (laminated complexes) containing an aluminum foil or a barrier polymer or simply a structure monolayer but with the necessary impermeability, the permeability of the outer tube being indifferent. Nor would a reduction in wall thickness be possible in the case of injected tubes, since this decrease would significantly affect the complexity to obtain a good filling of the injection cavity. To solve this circumstance it is known in the world of plastic injection the use of more fluid polymers to be able to manufacture a finer wall article; However, this increase in fluidity usually entails a change in critical properties, such as ESCR resistance. An additional advantage, offered by at least some embodiments of the invention and in particular by those in which the Tubular container recovers its outer shape after use, it is that the tubular container provides better ergonomics of use. This is due to the fact that in order to extract product, a pressure must always be applied on an expanded tubular container, as if it were completely filled, resulting in a more comfortable operation for the user's hand. Another advantage of these embodiments is that the tubular container can retain an immutable exterior appearance, that is, it can remain as new despite being used repeatedly and therefore can retain an optimal exterior appearance throughout its useful life. This is true even in those embodiments in which the tubular container is "airless", since it is the inner container that remains deformed while the outer tube recovers the original shape.

An additional advantage, offered by at least some embodiments of the invention and in particular by those in which a shoulder of the inner container is fixed internally to the head of the outer tube, is that a more effective and resistant fixing between both tubes compared to conventional double tube solutions in which both tubes have a head and in which the two tube heads are assembled together. In addition, said embodiments also improve the restitution rate compared to said conventional bi-tube solutions in which the fixation of the two tubes by their respective heads is performed. This increase in the restitution rate is achieved since the solutions existing so far did not allow a complete or almost complete collapse of the head of the inner container, even if it was manufactured with less thickness than the head of the outer tube. In contrast, in the tubular container of the present invention, the shoulder of the inner container is flexible, preferably being manufactured by a laminated, plastic or metalloplastic complex, and is welded by the inner part of the outer tube head, allowing its collapse as consequence of shoulder flexibility.

Another advantage, offered by at least some embodiments of the invention and in particular by those in which the distal end of the inner container is widened and attached to the distal end of the tube externally, the sealing of the distal end of the tubular container is significantly improved.

Brief description of the figures

The details of the invention can be seen in the accompanying figures, not intended to be limiting of the scope of the invention: - Figure 1 shows a sectional elevation of an outer tube of a tubular container according to an embodiment of the invention, the outer tube comprising a skirt, a head, and two unidirectional valves.

 - Figure 2 shows a sectional elevation of a skirt and shoulder manufactured separately, to form an inner container of a tubular container according to an embodiment of the invention.

 - Figure 3 shows a sectional elevation of the skirt and shoulder of the previous figure, joined together forming the inner container.

 - Figure 4 shows a sectional elevation of the inner container being introduced into an inner space of the outer tube.

 - Figure 5 shows a sectional elevation of the inner container completely inserted into the inner space of the outer tube.

 - Figure 6 shows a sectional elevation of the distal end of the skirts of the outer and inner tubes in the situation of Figure 5.

 - Figure 7 shows a sectional elevation of a conical piece being introduced by the distal end of the outer and inner tubes.

 - Figure 8 shows a sectional elevation of the distal end of the skirts of the outer and inner tubes once the conical part of Figure 7 has been removed.

- Figure 9 shows a sectional elevation of a tubular container formed by the outer tube and the inner container.

 - Figure 10 shows an enlarged view of the head of the outer tube and the shoulder of the inner container, and in particular of a unidirectional valve disposed in the head of the outer tube in communication with an intermediate cavity between both tubes.

 - Figure 1 shows a sectional elevation of the sealed tubular container at the distal end and containing a product inside.

 - Figure 12 shows an external perspective view of the tubular container in the situation of Figure 1 1.

 - Figure 13 shows a sectional elevation of the tubular container of Figure 1 1, in a situation in which two opposing forces are being applied and compressing the container for the extraction of product from its interior.

 - Figure 14 shows a sectional elevation of the tubular container of Figure 1 1, in a subsequent situation in which the application of the torque has ceased, and the outer tube has regained its non-deformed shape while the inner container remains deformed.

Detailed description of the invention

The invention relates to a tubular container of flexible material for housing a cosmetic, food, medicament or the like, and to a method of manufacturing said tubular container of flexible material. This type of tubular packaging is frequently characterized by comprising a hollow body or skirt, intended to contain a product (for example, a cosmetic cream), and a head arranged at one end of the skirt and intended to allow the product to be evicted or dosed. . The head may be provided with a product outlet neck, a cap, metering mechanisms, etc. Manufacturers of this type of tubular containers generally provide tubular containers to product marketers (for example, cosmetic products) with the head of the container closed, capped, sealed and generally finished, and with the opposite end of the skirt open. The Product marketers fill the tubular containers with their product through the open end of the skirt, and subsequently seal said end of the skirt, leaving the tubular container and product contained therein ready for sale to the public.

Figure 9 shows an exemplary embodiment of a tubular container (1) of flexible materials according to the invention. The tubular container (1), like other flexible tubular containers known in the state of the art, comprises a skirt (2) and a head (3). The skirt (2) is an elongated, hollow and optionally cylindrical body, arranged around a longitudinal central axis (4) and provided with a proximal end (5) and a distal end (6). The head (3) is arranged at the proximal end (5) of the skirt (2) and provides a closure to said proximal end (5). The head (3) of the tubular container can include various elements, such as anchoring systems of other parts, partial perforation shutters, useful for coupling for example closing caps of different shapes, dosing caps, metering pumps, applicators, drip systems, anti-return systems , etc. As can be seen in Figure 9, the tubular container (1) of the present invention is composed of an outer tube (10) and an inner container (30) housed inside the outer tube (10).

The outer tube (10), which is illustrated alone in Figure 1, comprises a skirt (1 1) and a head (12). The skirt (1 1) is an elongated, hollow and optionally cylindrical body, arranged around a longitudinal central axis (13) and having an inner space (14) and an inner diameter (d1), and also having a proximal end (15) and of a distal end (16). The head (12), meanwhile, is arranged at the proximal end (15) of the skirt (1 1) and is intended to close the outer tube (10) while allowing dosing through a product housed inside the tubular container (1). In various embodiments of the invention, the head may have different designs or configurations depending on the application or utility of the tubular container (1). For example, the head may have a simple exit hole and an external thread for coupling a threaded plug. In In other embodiments, the head may have a closure system coupled to the head, such as a stopper, a metering pump, or another. In the present embodiment, the head (12) comprises a shoulder (17), a generally cylindrical platform (18) arranged next to the shoulder (17) and a threaded neck (19) arranged next to the platform (18) and intended to receive a screw cap, a pump, an applicator or other part or mechanism (not shown). The threaded neck (19) ends in a transverse wall (20) provided with a hole (21). The head (12) delimits an interior space (22), which in the present embodiment extends from the interior space (14) of the skirt (1 1) to the hole (21) of the transverse wall (20).

Optionally, in the hole (21) of the transverse wall (20) a unidirectional valve (23), of the type of known unidirectional valves that allow the eviction of product from the inside of the tube to the outside and preventing the return of product and air from the outside to the inside of the tube. For example, the unidirectional valve (23) shown in the figure comprises a sphere (23a) that closes in a conical seat (23b); the sphere (23a) has axial freedom of movement, allowing the passage of product contained in the interior space (14, 22) when a pressure is exerted on the outer tube (10), and closing the passage of air from the outside into the interior space (14, 22) of the tube, when such pressure disappears and a depression appears inside (as explained below with reference to Figures 13 and 14).

Also, in certain embodiments of the present invention, the outer tube (10) may include at least one hole (24) made in the skirt (1 1) and / or in the head (12) of the outer tube (10) to provide an air passage between the outside of the outer tube (10) and the inner space (14, 22) of the outer tube (10). For example, in the present embodiment a hole (24) is included in the platform (18) of the head (12) of the outer tube (10), which communicates the inner space (14, 22) with the outer space ( not numbered). In certain embodiments, such as in the present embodiment, a unidirectional valve (25) can be arranged in the hole (24), the function of the unidirectional valve (25) allowing air to enter from the outside of the outer tube (10) into the inner space (14, 22) a through the hole (24) and prevent the passage of air from the inner space (14, 22) to the outside of the outer tube (10) through the hole (24). For example, the unidirectional valve (25) of the present embodiment, as can be seen in the enlarged view of Figure 10, is formed as a plug inserted in the orifice (24) and provided with a flexible conical plug (26) whose distal end (lower end in the figure) opens when the air pressure outside the tube is greater than the air pressure inside the tube, and closes when the air pressure inside the tube is greater than the outside air pressure to the tube As can be seen in Figure 9, the orifice (24) and the unidirectional valve (25) of the present embodiment are axially oriented, that is, in the direction of the longitudinal central axis (13) and in an area of the platform (18) adjacent to the shoulder (17).

The outer tube (10) can be decorated by techniques such as offset, flexography, screen printing, stamping (in English, "stamping"), self-adhesive labels, or mold labeling (IML).

As can be seen in Figure 3, the inner container (30), in turn, comprises a skirt (31) and a shoulder (32). The skirt (31) is an elongated, hollow and optionally cylindrical body, arranged around a longitudinal central axis (33) and having an interior space (34). The skirt (31) of the inner container (30) also has a proximal end (35), a distal end (36) and an outer diameter (d2), said outer diameter (d2) being preferably slightly smaller than the inner diameter (d1 ) of the skirt (1 1) of the outer tube (10). The shoulder (32) of the inner container (30) is disposed at the proximal end (35) of the skirt (31) and is formed by a wall that partially closes said proximal end of the skirt (31) and ends at an edge ( 38). The shoulder (32) is flexible and has an interior space (39). In turn, the edge (38) delimits a hole (37) that communicates the interior space (39) with the exterior of the inner container (30). Preferably, as is the case of the present embodiment, the wall forming the shoulder (32) is substantially conical, and the edge (38) and the hole (37) are concentric and its center is disposed on the longitudinal central axis (33) of the inner container (30). In certain embodiments, the shoulder (32) may have a constant thickness. In other embodiments, such as that illustrated herein, the edge (38) is thicker than the rest of the shoulder (32). Also contemplated are embodiments in which the shoulder (32) comprises at least one notch or area of reduced thickness, not shown, for example in the form of a ring arranged around the longitudinal central axis (33), whose function is detailed below. .

As mentioned above, the inner container (30) is disposed within the outer tube (10), that is, in the inner space (14) of the skirt (1 1) and in part of the inner space (22) of the head (12) of the outer tube (10). As can be seen in Figure 9, the shoulder (32) of the inner container (30) is in contact with the head (12) of the outer tube (10) along the entire perimeter of the shoulder (32), said contact being of such that a tight connection (40) is defined between the shoulder (32) and the head (12). Preferably, said seal (40) between the shoulder (32) and the head (12) consists of a weld joint. By means of the tight connection (40), the passage of fluids between the edge (38) of the shoulder (32) of the inner container (30) and the head (12) of the outer tube (10) is prevented; the passage of fluid is also prevented in all said seal (40), which extends along 360 ^Q around the longitudinal central axis (4) of the tubular container (1).

As can be seen, the seal (40), moreover, is arranged in a radially intermediate area of the head (12) of the outer tube (10), radially closer to the longitudinal central axis (4) than the skirt (31) of the inner container (30) and more specifically at an edge (27) of the platform (18) adjacent to the inner space (22). In certain embodiments, said edge (27) of the head (12) of the outer tube (10) may be provided with a seat or projection towards the interior space (22), not shown, whose function is detailed below. In addition, as mentioned above, the outer diameter (d2) of the skirt (31) of the inner container (30) is slightly smaller than the inner diameter (d1) of the skirt (1 1) of the outer tube (10), so that a clearance is defined between the skirt (1 1) of the outer tube

(10) and the skirt (31) of the inner container (30). This difference in diameter is such that it allows the flare of the inner container (30), as will be explained later with reference to Figures 7 and 8, the skirt (31) of the inner container (30) has deformability enough to fit the inside diameter (d1) of the skirt

(1 1) of the outer tube (10).

At the distal end (6) of the skirt (2) of the tubular container (1), in turn, the distal ends (16, 36) of the outer tube (10) and the inner container (30) are arranged. As can be seen in the enlarged view of Figure 8, the skirt (31) of the inner container (30) comprises a widened area (41) at the distal end (36) of the skirt (31). A length (h2) of said widened area (41) is attached against and in contact with the distal end (16) of the skirt (1 1) of the outer tube (10), preferably in the entire perimeter of the skirt (1 1 ) of the outer tube (10) around the central longitudinal axis (4) of the tubular container (1).

In certain embodiments, the distal ends (16, 36) of the skirts (1 1, 31) of the outer tube (10) and the inner container (30) are welded or glued together in the length contact zone (h2). The weld or the adhesive can cover the entire perimeter around the central longitudinal axis (4) or be intermittent. Also, welding or adhesive may cover all or part of the length (h2). The function of welding or adhesive is twofold. A first function is that welding or adhesive ensures that the distal ends (16, 36) of the skirts (1 1, 31) of the outer tube (10) and the inner container (30) are kept in contact and attached until When it is time to seal the distal end (6) of the tubular container (1) after filling said product container. It should be taken into account that, from the time the tubular container (1) of Figure 9 is manufactured until it is filled with product and sealed at its distal end (6) it can After some time and the tubular container (1) is subjected to transport, storage, handling, etc. of the tubular container (1), which could lead to possible unwanted mechanical actions on the tubular container (1). Welding or adhesive contribute to the contact in length (h2) being maintained despite such possible mechanical actions, as an intimate connection is achieved between the inner container (30) and the outer tube (10) in the seal end of the distal end (6) of the tubular container (1). A second function of welding or adhesive, in the particular case where said welding or adhesive is total perimeter, is to ensure that the inner wall of the distal end (16) of the skirt (1 1) of the outer tube (10) It is perfectly welded to the outer wall of the distal end (36) of the skirt (31) of the inner container (30). In this way, the product marketer, when sealing the distal end (6) of the tubular container (1) after filling the container with a product, should only worry about obtaining a good weld of the inner container (30), and that the outer tube (10) is supplied already welded. This solution helps the tubular container (1), from the point of view of the product marketer to fill the container and seal its distal end (6), behave as if it were monolayer (monotube), which facilitates considerably the sealing operation of the distal end (6) since the systems normally used introduce a nozzle with very low tolerances with respect to the tube walls. Above said widened area (41), as can be seen in Figure 8, the intermediate cavity (7) mentioned above is delimited. Therefore, as shown in Figures 8 and 9, the intermediate cavity (7) is delimited by the head (12) of the outer tube (10), the shoulder (32) of the inner container (30) and the skirts ( 1 1, 31) of the outer tube (10) and the inner container (30).

In certain embodiments, as is the case illustrated in the figures, the outer tube (10) and the inner container (30) are formed with dimensions such that the distal end (16) of the skirt (1 1) of the outer tube (10) protrudes a length (h1) with respect to the distal end (36) of the skirt (31) of the inner container (30), such as It can be seen in Figure 8.

An example of a method of manufacturing a tubular container according to the invention, for the manufacture of the above tubular container (1), is detailed below. Then, the methods of use of the tubular container (1) by the product marketer and by the end user will be detailed, in order to explain advantageous effects of the invention.

Figures 1 to 10 show a manufacturing sequence of the tubular container (1) according to an embodiment of the manufacturing method according to the invention.

In an initial step of the procedure, the outer tube (10) detailed above is provided, provided with skirt (1 1) and head (12), illustrated in Figure 1. The outer tube (10) can be manufactured in one or several phases by means of any conventional technique known in the field of manufacturing flexible tubular containers. For example, the outer tube (10) can be manufactured by extrusion of the skirt (1 1) and subsequent over-injection of the head (12). In other embodiments, the outer tube (10) can be manufactured by a mold injection of the skirt (1 1) and a subsequent mold injection of the head (12) onto the skirt (1 1). In another example, the complete outer tube (10) can be manufactured by injecting together the skirt (1 1) and the head (12). The outer tube (10) may be made of a formulation comprising one or more plastic materials such as polypropylene, polyethylene, copolymers, etc. The fabrication of the outer tube (10) can comprise the decoration of the tube by techniques such as offset, flexography, screen printing, stamping (in English, "stamping"), self-adhesive labels, or labeling in mold (IML).

In another initial step of the procedure, which can be executed before, after or in parallel to the previous step, the inner container (30) provided with a skirt (31) and a shoulder (32) is manufactured. The skirt (31) and the shoulder (32) can be made from plastic, metal or combinations of both. The skirt (31) and shoulder (32) can be manufactured together or, alternatively, separately and then joined, as shown in Figures 2 and 3. More specifically, and by way of example, the skirt (31) can be obtained from a sheet of plastic material (eg polyethylene), from a sheet of a metalloplastic complex ( eg an aluminum layer with an outer coating or an inner layer of polyethylene or polypropylene using in addition the necessary adhesives to make the bonding between layers possible, from a sheet of a plastic complex (eg a layer EVOH with an outer coating and / or an inner layer of polyethylene or polypropylene also using the necessary adhesives) or by other plastics transformation techniques such as extrusion or injection. In the case of using a sheet, the sheet is deformed or flexed until it acquires a tubular shape, for example cylindrical. Next, the opposite longitudinal edges of the sheet are welded or sealed to obtain a tubular sleeve. The soldier is made by generating heat in the area of tiling. The heat causes the polymers present in the opposite longitudinal edges to melt and adhere to each other. This is a manufacturing system known and used in the manufacture of laminated tubes intended to contain, for example, toothpastes. The heat generation can be carried out by means of a conventional resistance system, or by a high frequency magnetic field (in the case of splitting from a metalloplastic sheet), among others. Finally, the skirt (31) is obtained by cutting a predetermined length of the tubular sleeve. In turn, the shoulder (32) of the inner container (30) can be manufactured, continuing with the example, from a sheet of plastic material (eg polyethylene), from a metalloplastic complex (e.g. an aluminum layer with an outer coating and / or an inner layer of polyethylene or polypropylene using also the necessary adhesives to make the bonding between layers possible, or from a sheet of a plastic complex (eg a layer of EVOH with an outer coating and / or an inner layer of polyethylene or polypropylene also using the necessary adhesives). Portions of the sheet are cut and each portion is provided with a hole. Next, the portions are placed in a mold and a pressure or stamping is applied, giving the portions a three-dimensional truncated conical shoulder shape as illustrated in the figures, where the hole of each portion constitutes the hole (37) of the shoulder ( 32). Although a conical shoulder (32) has been depicted, it contemplate alternative embodiments in which the shape of the shoulder (32) may vary.

Once the skirt (31) and the shoulder (32) of the inner container (30) are available, as shown in Figure 3, the shoulder (32) is welded to the proximal end (35) of the skirt (31), leaving both united. Welding can be done for example by hot air, conduction, ultrasound, etc. Welding can also be carried out by a high frequency magnetic field, in case both the skirt (31) and the shoulder (32) are made of a combination of plastic and metal.

Once the inner container (30) is obtained, as shown in Figure 4, the inner container (30) is inserted into the outer tube (10). More specifically, the shoulder (32) of the inner container (30) is inserted through the open distal end (16) of the skirt (1 1) of the outer tube (10) and the inner container (30) is advanced into the outer tube (10) and along the inner space (14) of the outer tube (10). There comes a time, as shown in Figure 5, that the shoulder (32) of the inner container (30), and more specifically the edge (38) surrounding the hole (37), contacts the inner wall of the head ( 12) of the outer tube (10), and more specifically the inner wall of the platform (18).

Next, the shoulder (32) of the inner container (30) is welded to the head (12) of the outer tube (10), for example by hot air, by conduction or by high frequency (in the case where the shoulder (32 ) and / or the head (12) are made of a combination of plastic and metal). By welding, the tight connection (40) is formed between the edge (38) of the shoulder (32) of the inner container (30) and the inner wall of the head (12) of the outer tube (10) explained above, and also remain fixed together the outer tube (10) and the inner container (30).

Once the inner container (30) is inserted and fixed to the outer tube (10), at the opposite end, as shown in Figure 6, the distal ends (16, 36) of the skirts (1 1, 31) remain of the outer tube (10) and the inner container (30) radially separated from each other for a slack or distance (r1). Said distance (M) is substantially equal to half the difference between the inner diameter (d1) of the skirt (1 1) of the outer tube (10) and the outer diameter (d2) of the skirt (31) of the inner container (30). In addition, the distal end (16) of the skirt (1 1) of the outer tube (10) can protrude a length (h1) with respect to the distal end (36) of the skirt (31) of the inner container (30), such As depicted in the figures. However, alternative embodiments are contemplated in which the distal end (16) of the skirt (1 1) of the outer tube (10) does not protrude from the distal end (36) of the skirt (31), that is, in which the length (h1) is zero.

Then, as illustrated in Figures 7 and 8, an optional additional step is performed consisting of flaring the distal end (36) of the inner container (30). In said step, the inner container (30), and optionally the outer tube (10), is subjected to a deformation that causes the widening of the open distal end (36) of the skirt (31) of the inner container (30) until its outer diameter (d2) substantially equals the inner diameter (d1) of the skirt (1 1) of the outer tube

(10) and therefore the distal end (36) of the skirt (31) of the inner container (30) is internally attached to the distal end (16) of the skirt

(1 1) of the outer tube (10). The deformation can be performed, for example, by axially inserting a conical piece (50) or piece of decreasing diameter through the open distal end (36) of the skirt (31) of the inner container (30) to a predefined depth. In certain embodiments, the deformation can be performed with heat application, in which case both distal ends (16, 36) are fused; In other embodiments, the deformation can be performed without application of heat, whereby both distal ends (16, 36) are attached. Once the conical piece (50) has deformed the distal end (36) of the skirt (31) of the inner container (30), the conical piece (50) is removed. In certain embodiments, as is the case of the illustrated embodiment, the distal end (16) of the skirt (1 1) of the outer tube (10) does not deform. In other embodiments, the distal end (16) of the skirt (1 1) of the outer tube (10) is deformed, and can recover its original cylindrical shape once the conical part (50) is removed. In other embodiments, the distal end (16) of the skirt (1 1) of the outer tube (10) deforms and does not recover its original cylindrical shape once the conical part (50) is removed. In any case, once the conical part (50) is removed, as shown in Figure 8, a length (h2) of the distal end (36) of the skirt (31) of the inner container (30) is attached against and in contact with the skirt (1 1) of the outer tube (10). In certain embodiments, simultaneously or subsequently to the deformation, a weld is applied or an adhesive is made, along all or part of the perimeter of the walls of the distal ends (16, 36) of the skirts (1 1, 31), so that said distal ends (16, 36) are not only attached but also joined in all or part of said perimeter.

Once the distal ends (16, 36) of the skirts (1, 31) of the outer tube (10) and the inner container (30) are attached by deformation, and optionally joined by welding or total or partial perimetral adhesive, the tubular container (1) of Figure 9 is obtained, characterized in that it has an outer tube (10) intended to be visible and felt by the consumer, and an inner container (30) intended instead to enter contact with the product that will be stored in the tubular container (1).

Finally, a plug (not shown) or any other optional additional element (if not already made) is added to the tubular container (1), and the tubular container (1) is delivered to a marketer of products such as cosmetic products for You can pack your products in the tubular container (1).

For the product marketer, the tubular container (1) according to the invention, even being formed by two tubes (the outer tube (10) and the inner container (30)), has the external appearance of a conventional tubular container and, Most importantly, it can be filled and sealed identically to a conventional tubular container. The head (12) of the outer tube (10) constitutes the head (3) of the tubular container (1), while the skirts (1 1, 31) constitute the skirt (2) of the tubular container (1). The distal ends (16, 36) of the skirts (1 1, 31) of the outer tube (10) and the inner container (30) are attached to each other, so that in the distal end (6) of the skirt (2) of the tubular container (1) there is a single opening that communicates with a single interior space of the tubular container (1) (which coincides with the interior space (34) of the inner container (30) )), allowing the filling of the tubular container (1) as usual.

The product marketer (eg cosmetic products) proceeds to fill the tubular container (1) with a certain product (51) (represented in Figures 1 1, 13 and 14), for example a cream, introducing said product ( 51) in the inner space (34, 39) of the inner container (30) through the open distal end (6) of the tubular container (1). Then, as shown in Figure 1 1, a welding of the distal end (6) of the skirt (2) of the tubular container (1) is carried out, for example by applying to the skirt (2) heat, high frequency, an adhesive, etc. and subsequently applying a pressure on said distal end (6) of the skirt (2) that flattens said distal end (6) and causes it to seal in the form of a straight closure as can be seen in Figure 12. More specifically, the sealing it is made in a strip of the distal end (6) that has a height (h3) equal to part of, or all, the length (h2) of the widened area (41) of the distal end (36) of the skirt (31) of the inner container (30), if any, the length (h1) left over from the skirt (1 1) of the outer tube (10). This results in an intimate and resistant connection between the two skirts (1 1, 31) along the entire perimeter of the skirts (1 1, 31) along the widened area (41) and, optionally, a sealed end of the skirt (1 1) of the outer tube (10) on itself along the length (h1) left over of the skirt (1 1) of the outer tube (10). After welding, the product (51) housed in the inner space of the tubular container (1), and more specifically in the inner space (34, 39) of the inner container (30), as shown in Figure 1 one .

Figure 13 illustrates the product extraction process (51) inside the tubular container (1) by a user. As can be seen, when a user wishes to extract product (51) from inside the tubular container (1), the user generally applies two opposite lateral forces (F) with the help of the fingers or hands. The forces (F) cause a sinking into the skirt (1 1) of the tube outer (10) and a consequent increase in pressure in the intermediate cavity (7) between the outer tube (10) and the inner container (30). In the present embodiment, the unidirectional valve (25) of the outer tube (10) prevents the exit of air from the intermediate cavity (7), whereby the sinking of the skirt (1 1) and the increase in pressure in the intermediate cavity (7) in turn causes compression of the inner container

(30), and more specifically of the skirt (31) of the inner container (30). In alternative embodiments, one or more holes made in the outer tube (10), communicated with the intermediate cavity (7) and preferably devoid of valves could allow air to escape when compressing the outer tube (10) and that the tube outer (10) contact and push the inner container (30) causing compression of the skirt

(31) of the inner container (30). While the skirt (31) of the inner container (30) is compressed, welding of the edge (38) of the shoulder (32) of the inner container (30) against the head (12) of the outer tube (10) is maintained. . In the event that the shoulder (32) of the inner container (30) comprises one or more notches or areas of reduced thickness, said notches favor that, if necessary, the shoulder (32) can be flexed downwards when compression occurs of the skirt (31) without causing the shoulder edge (38) (32) to excessively pull the head (12) of the outer tube (10).

Compression of the skirt (31) of the inner container (30) causes an increase in pressure in the inner space (34, 39) of the inner container (30). When the pressure increase is sufficient, the product (51) begins to be dislodged through the hole (37) of the shoulder (32) of the inner container (30), the inner space (22) of the head (12) of the tube outside (10) and the unidirectional valve (23) at the head (12) of the outer tube (10). When the user ceases the application of forces (F), the skirt (31) of the outer tube (30), which has an elasticity and tendency to recover the original non-deformed shape, begins to open outwards, generating a vacuum in the cavity intermediate (7). Said vacuum causes outside air to enter through the unidirectional valve (25) or, in alternative embodiments, through one or more orifices without a valve, made in the outer tube (10) and communicated with the intermediate cavity ( 7). The air inlet in the intermediate cavity (7) contributes that the skirt (1 1) of the outer tube (10) ends up recovering its original shape, as shown in Figure 14. For its part, the unidirectional valve (23) of the head (12) of the outer tube (10) ) prevents the return of product (51) or outside air into the interior space (22) of the head (12) of the outer tube (10) and therefore into the interior space (34, 39) of the inner container (30). Accordingly, the inner container (30) remains in a deformed position, as shown in Figure 14. The fact that the seal (40) between the shoulder (32) of the inner container (30) and the head (12 ) of the outer tube (10) is made in an intermediate area of the head (12) of the outer tube (10) helps the deformed inner container (30) not to pull the outer tube (10) not deformed, and both can keep its deformed position and not deformed in a relaxed way. That is, the tubular container (1) described is able to keep its outer appearance intact after use (recovering after tightening a non-deformed aspect as illustrated in Figures 12 and 14), and also constitutes an airless type package. "(in English), with the advantages that this entails (mainly, that the product (51) remains isolated from the outside air, improving its conservation and extending its useful life).

Repeated uses of the tubular container (1) will produce increasing compression of the inner container (30), while the outer tube (10) is recovered as explained. Because the shoulder (32) has great deformability and is only attached to the head (12) of the outer tube (10) by a tight perimeter band (the tight joint (40)), the shoulder (32) can deform and fold inwards practically freely, achieving a very high collapse and restitution rate. If the edge (27) of the head (12) is provided with a projection or seat in which the sealed joint (40) is located, the folding of the shoulder (32) together with the skirt (31) can be favored. of the inner container (30) when the product is misaligned (51), the collapse of the inner container (30) being further favored and the restitution rate of the tubular container (1) is further improved. As mentioned above, in alternative embodiments, the intermediate cavity (7) is communicated with the outside through one or more permanent holes (ie, permanently open) made in the outer tube (10), for example in the shoulder (17) or on the skirt (1 1) of the outer tube (10). This results in a less expensive tubular container, lacking a unidirectional valve (25) and not requiring a mounting operation. The quantity and / or dimensions of the holes must provide an efficient and comfortable balance before the loss of pressure from the intermediate chamber and the speed of recovery of the original shape of the outer tube.

As regards the materials with which the outer tube (10) and the inner container (30) of the tubular container (1) are manufactured, it has been mentioned so far that both the outer tube (10) and the inner container ( 30) may be made of formulations of plastic materials, plastic complexes, metalloplastic complexes, one or more layers of a textile material, one or more layers of paper, combinations thereof, etc. In short, it is contemplated that the outer tube (10) and the inner container (30) can be made of any material or formulation applicable to tubes of flexible materials, such as polypropylenes, polyethylenes, polyolefin copolymers, complexes laminated with aluminum, complexes laminated with EVOH, etc. However, in a preferred embodiment of the invention the outer tube (10) is made of a plastic formulation and transformed by mold injection techniques, while the inner container (30) is preferably made of a plastic or metalloplastic formulation , and more specifically of plastic or metalplastic laminated complexes transformed by forming techniques.

Preferably, the material or materials from which the inner container (30) is manufactured satisfies one or more of the following requirements: impermeability requirements, ESCR resistance requirements, anti-slip requirements, food contact requirements, Pharmacopoeia requirements, flexibility requirements, deformability requirements, etc. This allows the inner container (30) to fulfill the functions described in this document. In turn, the material or materials from which the outer tube (10) is manufactured satisfies one or more different requirements such as processability requirements, surface appearance requirements, printability requirements (ability to receive an impression) , mechanical stiffness requirements (present a mechanical stiffness above a threshold value), etc .; In addition, the material or materials from which the outer tube (10) is manufactured may comprise recycled materials.

Preferably, the material or materials from which the outer tube (10) is manufactured does not satisfy (n) the requirements of the material or materials from which the inner container (30) is manufactured. That is, the outer tube (10) preferably does not meet the requirements of the inner container (30). For example, the materials of the outer tube (10) preferably do not satisfy requirements of impermeability, ESCR resistance, weldability, anti-slip, food contact, pharmacopoeia, flexibility and / or deformability that the materials of the inner container (30) do.

Preferably also, the material or materials from which the inner container (30) is manufactured does not satisfy the requirements of the material or materials from which the outer tube (1 0) is manufactured. That is, the inner container (30) preferably does not meet the requirements of the outer tube (10). For example, the materials of the inner container (30) preferably do not satisfy the processability, surface appearance, printability, mechanical stiffness and / or weldability requirements that the outer tube materials (10) meet. This separation of functional requirements into two components - the inner container (30) and the outer tube (10) - allows none of them to meet all the requirements simultaneously, and therefore facilitates the selection of materials for both tubes, impacting in a greater simplicity of manufacture and quality of the final tubular container (1) (understood as quality the ability to meet its functional requirements throughout the life of the tubular container (1)). In summary, the problem of the non-complete return of "airless" containers with double tube is solved using an inner container provided with a skirt and a shoulder in the form of a wall of decreasing diameter, which presents a better deformability compared to the deformation of the head of inner tubes known in the state of the art.

On the other hand, the problem of making a correct seal between the distal ends of an outer tube and an inner container, introduced in the outer tube, by deformation outwardly, widening or flaring the distal end of the inner container until it is attached is solved. to the distal end of the outer tube, and the subsequent sealing of both attached distal ends, forming an intimate union between said distal ends along the entire perimeter of both. It is contemplated that this solution can be applied in tubular containers alternative to that illustrated, for example in tubular containers where both the outer tube and the inner container comprise a respective skirt and a respective head.

In addition, the problem of the complexity of material selection is solved by creating a tubular container provided with an inner container intended to be hidden and in contact with the product to be stored, and an outer tube intended to be visible, where the materials of each of said tubes meet different functional requirements, and especially the outer tube does not meet the requirements of the inner container. It is contemplated that this solution can be applied in tubular containers alternative to that illustrated, for example in tubular containers where both the outer tube and the inner container comprise a respective skirt and a respective head

Claims

one . Tubular container (1) of flexible material, comprising: - an outer tube (10), provided with a skirt (1 1) and a head (12), where the skirt (1 1) has a proximal end (15) and a distal end (16), where the head (12) extends from the proximal end (15) of the skirt (1 1), and where the skirt (1 1) and the head (12) delimit an interior space (14, 22) communicable with the exterior of the outer tube (10) through a hole (21) in the head (12); - an inner container (30), provided with a skirt (31) and a flexible shoulder (32), where the skirt (31) has a proximal end (35) and a distal end (16), where the shoulder (32) extends from the proximal end (35) of the skirt (31), and where the skirt (31) and the shoulder (32) delimit an interior space (34, 39) and the shoulder (32) ends at an edge (38 ) delimiting a hole (37) communicated with said interior space (34, 39); where - the inner container (30) is arranged in the inner space (14, 22) of the outer tube (10), and the shoulder (32) of the inner container (30) is fixed to the head (12) of the outer tube (10), the hole (21) of the head (12) of the outer tube (10) being communicated with the inner space (34, 39) of the inner container (30). 2. Tubular container (1) according to claim 1, characterized in that it comprises at least one unidirectional valve (23) that allows the exit of a fluid from the inner space (34, 39) of the inner container (30) to the outside of the outer tube (10) and preventing the entry of air from the outside of the outer tube (10) into the inner space (34, 39) of the inner container. 3. Tubular container (1) according to claim 2, characterized in because said unidirectional valve (23) is arranged in the hole (21) of the head (12) of the outer tube (10). 4. Tubular container (1) according to claim 1, characterized in that the skirt (31) of the inner container (30) does not protrude from the skirt (1 1) of the outer tube (10). 5. Tubular container (1) according to claim 1, characterized in that the shoulder (32) of the inner container (30) is attached to the head (12) of the outer tube (10) by the edge (38) of the shoulder (32). 6. Tubular container (1) according to claim 1, characterized in that the shoulder (32) is attached to the head (12) of the outer tube (10) along a tight joint (40) arranged continuously along a full perimeter around a central longitudinal axis (4) of the tubular container (1). 7. Tubular container (1) according to claim 1, characterized in that an intermediate cavity (7) is defined between the outer tube (10) and the inner container (30). 8. Tubular container (1) according to claim 7, characterized in that the shoulder (32) is attached to the head (12) of the outer tube (10) along a tight joint (40) arranged continuously along a full perimeter around a central longitudinal axis (4) of the tubular container (1). 9. Tubular container (1) according to claim 8, characterized in that said intermediate cavity (7) is radially more external with respect to the longitudinal central axis (4) than the seal (40). 10. Tubular container (1) according to claim 9, characterized in that the shoulder (32) of the inner container (30) is only attached to the head (12) of the outer tube (10) along said tight connection (40), the rest of the shoulder (32) being arranged radially more external to the seal (40) and separated from the outer tube (10). eleven . Tubular container (1) according to claim 8, characterized in that the intermediate cavity (7) extends from the tight junction (40) to the distal end (36) of the skirt (31) throughout the perimeter of the skirt (31) and shoulder (32) around a central longitudinal axis (4) of the tubular container (1). 12. Tubular container (1) according to claim 1, characterized in that the distal end (36) of the skirt (31) of the inner container (30) is in contact with the distal end (16) of the skirt (1 1) of the outer tube (10). 13. Tubular container (1) according to claim 9, characterized in that the distal end (36) of the skirt (31) of the inner container (30) is in contact with the distal end (16) of the skirt ( 1 1) of the outer tube (10) along a complete perimeter around the central longitudinal axis (4). 14. Tubular container (1) according to claim 10, characterized in that the distal end (36) of the skirt (31) of the inner container (30) is fixed to the distal end (16) of the skirt (1 1 ) of the outer tube (10) in at least part of said perimeter. 15. Tubular container (1) according to claim 7, characterized in that the outer tube (10) comprises at least one hole (24) that communicates the intermediate cavity (7) with the outside of the outer tube (10). 16. Tubular container (1) according to claim 15, characterized in that in said hole (24) there is a unidirectional valve (25) that allows the entry of air from outside the outer tube (10) into the cavity intermediate (7) and that prevents the exit of air from the intermediate cavity (7) to the outside of the outer tube (10). 17. Tubular container (1) according to claim 16, which characterized in that said intermediate cavity (7), said orifice (24) and said unidirectional valve (25) are radially more external with respect to the longitudinal central axis (4) than the seal (40). 18. Method of manufacturing a tubular container (1) of flexible material, comprising the steps of: - obtaining an outer tube (10) provided with a skirt (1 1) and a head (12), where the skirt (1 1) has a proximal end (15) and a distal end (16), where the head (12 ) extends from the proximal end (15) of the skirt (1 1), and where the skirt (1 1) and the head (12) delimit an interior space (14, 22) communicable with the exterior of the outer tube (10 ) through a hole (21) in the head (12); - obtaining an inner container (30), provided with a skirt (31) and a flexible shoulder (32), where the skirt (31) has a proximal end (35) and a distal end (16), where the shoulder (32 ) extends from the proximal end (35) of the skirt (31), and where the skirt (31) and shoulder (32) delimit an interior space (34, 39) and the shoulder (32) ends at an edge ( 38) delimiting a hole (37) communicated with said interior space (34, 39); where - insert the inner container (30) into the inner space (14, 22) of the outer tube (10), and - fix the shoulder (32) of the inner container (30) to the head (12) of the outer tube (10), the hole (21) of the head (12) of the outer tube (10) being communicated with the inner space ( 3. 4, 39) of the inner container (30). 19. Method according to claim 18, characterized in that the step of obtaining an outer tube (10) comprises obtaining the skirt (1 1) of the outer tube (10) by extrusion and forming the head (12) of the outer tube (10) by superinjection in mold on the skirt (1 1) of the outer tube (10). 20. Method according to claim 18, characterized in that the step of obtaining an outer tube (10) comprises obtaining the skirt (1 1) of the outer tube (10) by injection in mold and forming the head (12) of the outer tube (10) by superinjection in mold on the skirt (1 1) of the outer tube (10). twenty-one . Method according to claim 18, characterized in that the step of obtaining an outer tube (10) comprises obtaining said outer tube (10) by means of a joint injection procedure in mold of the skirt (1 1) and the head (12 ) of the outer tube (10). 22. Method according to claim 18, characterized in that the step of obtaining an inner container (30) comprises obtaining the skirt (31) of the inner container (30) by extrusion and forming the shoulder (32) of the inner container (30) by mold injection into the skirt (31) of the inner container (30). 23. Method according to claim 18, characterized in that the step of obtaining an inner container (30) comprises obtaining the skirt (31) of the inner container (30) by injection in mold and forming the shoulder (32) of the container interior (30) by mold injection into the skirt (31) of the inner container (30). 24. Method according to claim 18, characterized in that the step of obtaining an inner container (30) comprises obtaining said inner container (30) by means of a joint injection procedure in mold of the skirt (31) and the shoulder ( 32) of the inner container (30). 25. A method according to claim 18, characterized in that the step of obtaining an inner container (30) comprises: obtaining a first sheet of a plastic or metalloplastic complex, deforming said first sheet until a tubular shape is acquired, sealing adjacent edges of the tubular shape to maintain the tubular shape, obtaining the skirt (31) of the inner container (30); get a second sheet of a plastic or metalloplastic complex; providing said second sheet with a hole; applying a pattern to said second sheet provided with said hole, the shoulder (32) of the inner container (30) being formed; and fixing said shoulder (32) of the inner container (30) to said skirt (31) of the inner container (30). 26. Tubular container (1) of flexible material, comprising: - an outer tube (10), provided with a skirt (1 1) and a head (12), where the skirt (1 1) has a proximal end (15) and a distal end (16), where the head (12 ) extends from the proximal end (15) of the skirt (1 1), and where the skirt (1 1) and the head (12) delimit an interior space (14, 22) communicable with the exterior of the outer tube (10 ) through a hole (21) in the head (12); - an inner container (30), provided with a skirt (31) having a proximal end (35) and a distal end (16); where - the inner container (30) is disposed in the inner space (14, 22) of the outer tube (10), and the distal end (36) of the skirt (31) of the inner container (30) is flared and in contact with the distal end (16) of the skirt (1 1) of the outer tube (10). 27. Tubular container (1) according to claim 26, characterized in that the distal end (36) of the skirt (31) of the inner container (30) is flared and in contact with the distal end (16) of the skirt (1 1) of the outer tube (10) in a complete perimeter around a longitudinal central axis (4) of the tubular container (1). 28. Tubular container (1) according to claim 26, characterized in that the distal end (36) of the skirt (31) of the inner container (30) is arranged flush with the distal end (16) of the skirt ( 1 1) of the outer tube (10). 29. Tubular container (1) according to claim 26, characterized in that the distal end (16) of the skirt (1 1) of the outer tube (10) protrudes a length (h1) of the distal end (36) of the skirt (31) of the inner container (30). 30. Tubular container (1) according to claim 26, characterized in that the distal end (36) of the skirt (31) of the inner container (30) is fixed to the distal end (16) of the skirt (1 1 ) of the outer tube (10) in at least part of a perimeter around a central longitudinal axis (4) of the tubular container (1). 31. Tubular container (1) according to claim 30, characterized in that the distal end (36) of the skirt (31) of the inner container (30) is fixed to the distal end (16) of the skirt (1 1) of the outer tube (10) by a weld, an adhesive or a combination of both. 32. Method of manufacturing a tubular container (1) of flexible material, comprising the steps of: - obtaining an outer tube (10) provided with a skirt (1 1) and a head (12), where the skirt (1 1) has a proximal end (15) and a distal end (16), where the head (12 ) extends from the proximal end (15) of the skirt (1 1), and where the skirt (1 1) and the head (12) delimit an interior space (14, 22) communicable with the exterior of the outer tube (10 ) through a hole (21) in the head (12); - obtaining an inner container (30) provided with a skirt (31), wherein said skirt (31) has a proximal end (35) and a distal end (16); - insert the inner container (30) into the inner space (14, 22) of the outer tube (10); Y - flare the distal end (36) of the skirt (31) of the inner container (30), the distal end (36) of the skirt (31) of the inner container (30) being flared and in contact with the distal end (16 ) of the skirt (1 1) of the outer tube (10). 33. A method according to claim 32, characterized in that the step of flaring the distal end (36) of the skirt (31) of the inner container (30) comprises flaring a full perimeter of the distal end (36) of the skirt (31) of the inner container (30) around a central longitudinal axis (4) of the tubular container (1), the distal end (36) of the skirt (31) of the inner container (30) being flared and in contact with the distal end (16) of the skirt (1 1) of the outer tube (10) along said entire perimeter. 34. A method according to claim 32, characterized in that the step of flaring the distal end (36) of the skirt (31) of the inner container (30) comprises introducing a conical piece (50) into said distal end (36 ) of the skirt (31) of the inner container (30) and deform the distal end (36) of the skirt (31) of the inner container (30) against the distal end (16) of the skirt (1 1) of the outer tube (10) 35. A method according to claim 32, characterized in that the step of inserting the inner container (30) comprises inserting the inner container (30) until the distal end (36) of the skirt (31) of the inner container ( 30) is disposed flush with the distal end (16) of the skirt (1 1) of the outer tube (10). 36. A method according to claim 32, characterized in that the step of inserting the inner container (30) comprises inserting the inner container (30) until the distal end (16) of the skirt (1 1) of the outer tube (10) a length (h1) of the distal end (36) of the skirt (31) of the inner container (30) protrudes. 37. A method according to claim 32, characterized in that it comprises the additional step of fixing the distal end (36) of the skirt (31) of the inner container (30) to the distal end (16) of the skirt (1 1 ) of the tube exterior (10) in at least part of a perimeter around a central longitudinal axis (4) of the tubular container (1). 38. A method according to claim 37, characterized in that said step of fixing the distal end (36) of the skirt (31) of the inner container (30) comprises welding, adhesive or a combination of both. 39. Method according to claim 32, characterized in that the step of obtaining an outer tube (10) comprises obtaining the skirt (1 1) of the outer tube (10) by extrusion and forming the head (12) of the outer tube (10) by superinjection in mold on the skirt (1 1) of the outer tube (10). 40. Method according to claim 32, characterized in that the step of obtaining an outer tube (10) comprises obtaining the skirt (1 1) of the outer tube (10) by injection in mold and forming the head (12) of the outer tube (10) by superinjection in mold on the skirt (1 1) of the outer tube (10). 41. Method according to claim 32, characterized in that the step of obtaining an outer tube (10) comprises obtaining said outer tube (10) by means of a joint injection procedure in mold of the skirt (1 1) and the head (12 ) of the outer tube (10). 42. Method according to claim 32, characterized in that the step of obtaining an inner container (30) comprises obtaining the skirt (31) of the inner container (30) by extrusion. 43. Method according to claim 32, characterized in that the step of obtaining an inner container (30) comprises obtaining the skirt (31) of the inner container (30) by injection in mold. 44. Method according to claim 32, characterized in that the step of obtaining an inner container (30) comprises obtaining a sheet of a plastic or metalloplastic complex, deforming said sheet until a tubular shape is acquired, seal adjacent edges of the tubular shape to maintain the tubular shape and obtaining the skirt (31) of the inner container (30). 45. Tubular container (1) of flexible material, comprising a skirt (2), a head (3) and an interior space to house a product (51), comprising: - an outer tube (10), provided with a skirt (1 1) and a head (12), where the skirt (1 1) has a proximal end (15) and a distal end (16), where the head (12 ) extends from the proximal end (15) of the skirt (1 1), and where the skirt (1 1) and the head (12) delimit an interior space (14, 22) communicable with the exterior of the outer tube (10 ) through a hole (21) in the head (12); - an inner container (30), arranged in the inner space (14, 22) of the outer tube (10), and having an inner space (34, 39) that provides at least part of the inner space of the tubular container (1) and that it is communicated with the hole (21) of the head (12) of the outer tube (10); where - at least part of the inner container (30) is made of a first material or first combination of materials configured to meet a first requirement; Y - at least part of the outer tube (10) is made of a second material or second combination of materials not configured to meet said first requirement. 46. Tubular container (1) according to claim 45, characterized in that said first requirement is a waterproof requirement. 47. Tubular container (1) according to claim 45, characterized in that said first requirement is a resistance requirement ESCR. 48. Tubular container (1) according to claim 45, characterized in that said first requirement is an anti-delamination requirement. 49. Tubular container (1) according to claim 45, characterized in that said first requirement is a food contact requirement. 50. Tubular container (1) according to claim 45, characterized in that said first requirement is a pharmacopoeia requirement. 51. Tubular container (1) according to claim 45, characterized in that said first requirement is a flexibility requirement. 52. Tubular container (1) according to claim 45, characterized in that said first requirement is a deformability requirement. 53. Tubular container (1) according to claim 45, characterized in that the second material or second combination of materials comprises a recycled material. 54. Tubular container (1) according to claim 45, characterized in that the second material or second combination of materials is configured to meet a second requirement, which is not met by the first material or first combination of materials. 55. Tubular container (1) according to claim 54, characterized in that said second requirement is a processability requirement. 56. Tubular container (1) according to claim 54, characterized in that said second requirement is a surface aspect requirement. 57. Tubular container (1) according to claim 54, characterized in that said second requirement is a printability requirement. 58. Tubular container (1) according to claim 54, characterized in that said second requirement is a requirement of mechanical rigidity. 59. Method of manufacturing a tubular container (1) of flexible material, comprising a skirt (2), a head (3) and an interior space to house a product (51), comprising: - obtain first material or first combination of materials configured to meet a first requirement; - obtaining, using said first material or first combination of materials, an outer tube (10) provided with a skirt (1 1) and a head (12), where the skirt (1 1) has a proximal end (15) and a distal end (16), where the head (12) extends from the proximal end (15) of the skirt (1 1), and where the skirt (1 1) and the head (12) delimit an interior space (14, 22) communicable with the outside of the outer tube (10) through a hole (21) in the head (12); - obtain a second material or second combination of materials not configured to meet said first requirement; - obtaining, using said second material or second combination of materials, an inner container (30) provided with an interior space (34, 39); - inserting said inner container (30) into the inner space (14, 22) of the outer tube (10), said inner space (34, 39) providing at least part of the inner space of the tubular container (1) and said interior space remaining (34, 39) communicated with the hole (21) of the head (12) of the outer tube (10).