Title: Flexible sachet with double opening

Technical field

The present invention relates to flexible sachets intended for the packaging of hair compositions, and more particularly, but not exclusively, to those intended for the packaging of a hair dyeing composition.

Prior art

It is generally recommended that users of a hair dyeing composition carry out a patch test prior to applying the composition in order to see if there is any undesirable physiological reaction of the skin, such as an allergic reaction.

This “patch test” should preferably be carried out 48h before using the dye, by depositing a droplet of composition on a cutaneous surface and then checking whether this deposition gives rise to the appearance of redness or another undesirable effect, in which case it is not advised to apply the composition.

Hair dyes, notably oxidation dyes, are generally sensitive to oxygen and react when exposed to air for a protracted period of time. Thus, if the sachet containing the composition is opened for the patch test, in the process exposing the rest of the composition to air for the 48h waiting time, said composition runs the risk of being altered at least in terms of appearance, this possibly leading the user to think that the product is defective.

It is known to package the hair composition in two separate compartments of one and the same sachet, the one being used for the dye and the other, which is smaller, being used for the patch test.

Application JP2019116300 discloses a sachet with two compartments that can be detached by virtue of precut lines.

Patents FR2918038 and EP2758321 disclose sachets having two separate compartments made by welding two sheets to one another.

Application FR2262627 discloses a sachet which does not specifically concern carrying out a patch test or the packaging of a hair dye.

IT20012902054627 describes a sachet for the packaging of a solid product immersed in a liquid, such as mozzarella, which sachet has a drainage channel that can be freed up by removing the upper part of the sachet. Disclosure of the invention

There is a need to further improve sachets in order to be able to carry out a reliable patch test without thereby altering the quality of the composition intended for application to the hair, and without the proposed solution causing significant excess cost for manufacturing the sachet or posing logistics problems with respect to the known solutions.

Summary of the invention

The invention aims to achieve this object and, according to one of its aspects, relates to a flexible sachet containing at least one composition, preferably hair composition, notably hair dyeing composition, having at least two walls that are welded to one another and together define at least one compartment containing the composition, the sachet having a first opening zone that is to be cut in order to form a first opening for dispensing a limited amount of composition in order to carry out a patch test, the sachet having welding zones on the walls that are disposed so as to delimit between them an outlet passage of reduced width, communicating with said compartment and extending at least partially in the first opening zone, the sachet moreover having a second opening zone that is to be cut in order to form a second opening for emptying the sachet, the second opening zone cutting the compartment upstream of the outlet passage.

According to another of its aspects, the invention relates to a flexible sachet containing at least one hair composition, notably hair dyeing composition, having at least two walls that are welded to one another and together define at least one compartment containing the composition, the sachet having: a first opening zone having a first visual guide constituting a cut line, preferably a first imprint of a cut line, notably a broken line, in order to form, by cutting, a first opening of small cross section for dispensing a limited amount of composition in order to carry out a patch test, a second opening zone having a second visual guide constituting a cut line, preferably a second imprint of a cut line, notably a broken line, in order to form, by cutting, a second opening, of larger cross section than the first opening, for emptying the sachet, the second opening zone preferably cutting the compartment upstream of the first opening zone. A sachet according to one or the other of these aspects makes it possible to carry out a patch test using the same composition as that intended to be applied to the hair; the small cross section of the first opening limits the amount of composition which flows out and facilitates the removal of a small amount; the sachet can be produced simply, and it is not necessary to provide a separate compartment for specifically receiving the composition intended for the patch test; the sachet can be produced with a single compartment and the composition which is used for the test comes from the same compartment as that which will be used later on.

Moreover, the relative positions of the first and second opening zones make it possible, when the sachet is fully opened along the second opening, to discard that part of the sachet that runs the risk of containing a small amount of composition that has a deteriorated appearance following exposure to the ambient air through the opening made for the patch test.

In the following text, the terms “top”, “bottom”, “upper”, “lower”, “vertical” refer to a sachet that rests on its bottom against a horizontal planar surface and is oriented vertically. The vertical edge can correspond to a large side of the sachet when it is rectangular.

The terms “to cut (out)” and “cutting (out)” should be understood in the broad sense, that is to say denoting any action making it possible to make the opening in the sachet, irrespective of whether it is made manually, for example by tearing, or using a cutting tool such as scissors, a knife, a cutter or any other suitable means.

“Opening zone” denotes the region in which the cut that forms the opening is made.

The term “upstream” should be understood with a view to the direction of flow of the product when it is dispensed from the sachet.

The first opening zone and/or the second opening zone may have various indications regarding the cut to be made, for example an imprint of a cut line, notably an imprint of a broken line with a cutting tool, such as scissors. Other visual guides constituting the cut line may be used, such as a contrasting appearance, notably in terms of colours, this visual guide possibly resulting from an imprint or being formed in another way.

The outlet passage may form a channel, the length of which is preferably greater than or equal to 5 mm, better 10 mm, and the width of which is less than or equal to 10 mm over at least a portion of its length, preferably over a portion at least 5 mm long. Such dimensions make it possible to limit the flow rate of composition dispensed when the opening for the patch test is made and make it easier to obtain a satisfactory closure for the channel, which can be formed simply by pressing the two opposing walls against one another; in this way, the risk of the composition altering after the sachet has been opened to carry out the patch test is effectively limited.

The first opening may be made by cutting out a portion of the sachet extending between two adjacent free edges thereof, for example two edges oriented perpendicularly with respect to one another in the case of a rectangular sachet.

As a variant, the sachet may have a precut line extending in the first opening zone, the first opening being made by cutting off a portion of the sachet extending between a free edge thereof and said precut line. This cutting is made, for example, with scissors. The precut line guides the user to cut the sachet at the correct location and, after cutting, to leave a channel that is long enough to limit the exposure of the contents of the compartment to air. The precut line extends for example over a length less than or equal to half the total length of the channel.

The outlet channel may have the shape of a 90° bend, with preferably the one of the arms of the bend extending parallel to an edge of the sachet, notably a large side thereof. In this case, the precut line may extend along the terminal arm of the channel, over part of its length. Thus, in some embodiments, the compartment, in its upper part, communicates with an outlet passage which forms an outlet channel having the shape of a bend with two arms disposed substantially at 90° to one another, the terminal arm extending preferably parallel to the vertical free edge of the sachet. The bent shape contributes to limiting the amount of product dispensed during the patch test, and makes it possible to obtain sufficient closure so as to avoid the situation in which the composition that remains in the compartment and is intended to be applied to the hair is not subjected to oxidation following the opening of the channel. In particular, the proximal arm of the channel is preferably not affected by cutting the sachet in the opening zone, and may be closed again by pressing the walls of the sachet against one another.

The sachet preferably has a peripheral welding zone with a width wl at least in certain locations, the one of the welding zones bordering the outlet channel extending in the form of a wide strip of width w2>wl, notably a wide strip extending parallel to a vertical free edge of the sachet. This wide strip may be longer or shorter, and it may extend over a length of for example between 10% and 40% of the length of the sachet, notably between 10% and 30%, or even between 10% and 20%.

The welding zone extending in the form of a wide strip may be traversed by a precut line, notably a precut line having an oblique edge at one end. This precut line may have a substantially quarter- circle-shaped curve terminating at or close to the free edge of the sachet and, at the other end, said oblique edge, notably oriented substantially at 45° with respect to a vertical edge of the sachet. This precut line makes it possible to fully open the sachet with a view to applying the composition. The opening can be made manually or using scissors.

When the opening is made by tearing the sachet, the latter may have a tear starting point, for example in the form of a V-shaped notch.

The aforementioned oblique edge is preferably oriented along a straight line which defines the second opening.

With preference, the one of the welding zones forms an extension that extends from a peripheral welding zone adjoining a free edge of the sachet, notably an extension that extends downwards, said extension extending for example substantially parallel to a terminal portion of the outlet channel.

As mentioned above, the sachet may have a precut line extending along said extension as far as the free edge of the sachet, which facilitates the cutting of the opening zone in order to carry out the patch test. In particular, this precut line makes it possible to form a tab containing the terminal portion of the outlet channel, it being possible for the user to fold said tab before it is cut. The cutting may be performed at the folded part, which, because of being folded, is spaced apart from the rest of the sachet; this limits the risk of accidentally opening the sachet somewhere other than the outlet channel.

The walls that are welded to one another may be formed from a complex having at least one gasbarrier layer, for example a metallized layer, notably made of aluminium, a coating layer based on silicon oxides, or any other suitable layer, in a manner known per se.

The sachet may be formed in different ways, for example by folding a single sheet on itself and welding it to itself.

The sachet may have a bottom with a certain width, and two uprights that meet at this bottom by way of a fold line at their lower end, and are fixed to one another over a certain height from their upper end. Such a sachet may be considered as being of the 3D pouch or “Doypack” type.

The invention also relates to a hair dyeing method, having a step consisting in removing a test dose of hair composition from a sachet as defined above, by dispensing said dose through the outlet passage after having opened the sachet there, then in dispensing the rest of the composition in a different way than through the outlet passage, by making a new opening in the sachet. This new opening can be made by cutting the sachet in order to discard the part bearing the outlet channel. The cut may be performed with scissors by following the imprints or other visual guides present on the sachet.

Detailed description

It will be possible to better understand the invention from reading the following detailed description of non-limiting exemplary embodiments thereof, and from examining the appended drawing, in which:

[Fig la], [Fig lb] Figures la and lb partially and schematically show examples of a sachet according to the invention,

[Fig 2a], [Fig 2b] Figures 2a and 2b are partial and schematic front views of sachets according to the invention having imprint lines,

[Fig 3a], [Fig 3b] Figures 3a and 3b partially and schematically show various details of an embodiment of the sachet according to the invention,

[Fig 4] Figure 4 partially and schematically shows an example of a sheet that, by folding it on itself and welding it to itself, can form a sachet according to the invention, and

[Fig 5a], [Fig 5b] Figures 5a and 5b partially and schematically show variants of the sachet according to Figure la.

A flexible sachet 1 according to the invention is shown in Figure la. The sachet 1 defines a single compartment 2 that can accommodate a hair composition, for example a hair dye.

The compartment 2 is for example defined by two opposite walls 2a and 2b welded to one another and connected at a bottom 9, all three being visible in Figure 4, which shows the sheet used to manufacture the sachet.

The compartment 2, in its upper part, communicates with an outlet passage 3 which, in the example in question, forms an outlet channel having the shape of a bend with two arms 3a and 3b disposed substantially at 90° to one another, the terminal end 3b extending parallel to the vertical free edge lb of the sachet 1.

The arm 3b is defined between an extension 7c formed by welding the walls 2a and 2b to one another and the upper peripheral weld 7d of the sachet.

The arm 3b of the outlet channel has for example a width Lc less than or equal to 5 mm and its total length, defined by the sum of the lengths of the arms 3a and 3b, is for example greater than or equal to 10 mm, being for example 15 mm long. The sachet 1 has a first opening zone 4 that is to be cut and in which the arm 3b of the outlet channel extends.

The sachet has a second opening zone 6 that is to be cut in order to form a second opening for emptying the sachet, the second opening zone cutting the compartment 2 upstream of the outlet passage 3.

In the example illustrated in Figure la, a vertical precut line 5 starting at the horizontal upper edge la of the sachet and extending in the opening zone 4 along the extension 7c makes it possible to more easily cut the upper end of the outlet passage 3 at a cut line, and to dispense a small amount of composition from the compartment 2 in order to carry out a patch test.

In the variant illustrated in Figure lb, the opening zone 4 extends between the adjacent free edges la and lb of the sachet 1; the first opening is made by cutting off a comer of the sachet which includes the upper end of the outlet passage 3.

The sachet may have an imprint 100 of a cut line at the first and/or second openings, for example a broken line or another visual guide, with a cutting tool such as scissors, as illustrated in Figure 2a for the sachet of Figure la and in Figure 2b for the sachet of Figure lb.

The reduced width and the bent shape of the outlet passage 3 makes it possible to limit the flow rate of product dispensed through the first opening 4 and to restrict the interior space of the sachet, where the product could be exposed to oxidation following the opening of the passage for carrying out the patch test, to the zone of the outlet passage.

Since the second opening which makes it possible to empty the sachet 1 is located upstream of the outlet passage, when this opening is formed the portion of the sachet having the outlet passage and the product possibly oxidized following the patch test is discarded.

The dimensions of the channel, with or without a bend, and the position of the cuts can be adjusted in accordance with the desired flow rate, and the force needed to discharge the composition can be adjusted for example depending on the rheological behaviour and/or the viscosity thereof.

The peripheral welding zone 7a has a width wl in certain locations, extending in the form of a strip of width w2>wl in a zone 7b bordering the bottom of the outlet channel 3. For example, w2/wl > 1.2, notably is between 1.2 and 2.5.

This strip may have a length Lw that varies depending on the disposition of the second opening zone 6, as illustrated in Figures la and lb. For example, the length Lb of the zone 7b represents between 10% and 20% of the total length Lt of the sachet. The zone 7b may have an upper internal edge 120 which is oriented substantially perpendicularly to the large side of the sachet, and a lower internal edge 121 which is oriented obliquely.

In the example of Figures lb and 2b, the imprinted lines which constitute the cuts to be made end at the external free edge of the zone 7b.

The second opening may be formed in various ways, notably using a cutting tool or else manually. Manual opening may be facilitated by an opening starting point or a precut line, as illustrated in Figures 3a and 3b.

In the example illustrated in Figure 3a, the zone 7b of the sachet has a precut line 8 having, at its end 8b, a substantially quarter-circle- shaped curve up to the vicinity of the free edge lb of the sachet 1, and, at the other end 8a, an oblique edge oriented at 45° with respect to the vertical edge lb of the sachet.

Opening the sachet using the precut line 8 may be done manually by tearing the sachet in the continuation of the oblique edge at the end 8a, or by means of scissors.

In the variant illustrated in Figure 3b, the welding zone 7b has a tear starting point 60 in the form of a V-shaped notch at the vertical free edge lb of the sachet. The starting point 60 delimits an end of the second opening zone 6.

The sachet 1 may be produced in multiple ways, notable by folding and welding a single sheet 10, as illustrated in Figure 4.

With reference to Figure 4, it can be seen that the bottom 9, before manufacture, has a width Lf, for example of about 40 mm. When the sachet 1 is formed from a single sheet 10, as illustrated in Figure 2a, the walls 2a and 2b meet at the bottom 9 by way of fold lines 13, are welded to the portions 12a and 12b, respectively, of the bottom 9 located on either side of the median line 11, and are welded to one another in the peripheral zone 7a for the rest.

During the manufacture of the sachet 1, the following steps, for example, are followed:

The sheet 10 is folded along the median line 11 and the fold lines 13, so as to superpose the walls 2a and 2b,

The walls 2a and 2b are welded to one another and to the bottom 9 in the welding zones, apart from the zone 7d extending along the upper horizontal edge la of the sachet, so as to leave an opening in the upper edge 2d of the compartment 2,

The compartment 2 is filled with the composition through the opening in the upper edge 2d, The compartment 2 and the outlet passage 3 are closed by welding the walls 2a and 2b along the upper welding zone 7d.

To use the composition, first of all a small amount of product is removed through the outlet passage 3 by opening the sachet 1 in the opening zone 4 in order to carry out the patch test. Once the time for the test has elapsed, for example after 48h, a larger opening is made in the sachet 1 by cutting it, for example along a straight line D in the continuation of the precut line 8, in order to empty it of its contents. Such a cut eliminates the cut zone and the remaining product contained in the outlet passage 3.

Of course, the invention is not limited to the example which has just been described.

For example, the outlet passage is not necessarily a bent outlet channel. It may be a straight outlet channel, for example parallel to the upper edge la of the sachet 1, as illustrated in Figure 5a. In this case, a horizontal extension 7c is formed towards the interior of the compartment from the peripheral welding zone located along the vertical edge of the sachet.

In the variant of Figure 5b, the outlet passage 3 is a channel oriented at approximately 45° to the vertical edge, the peripheral welding zone being extended towards the interior in one comer of the sachet, and the passage being in the form of a notch formed in this extended zone.