WO2017001788A1 - Multilayer plastics container - Google Patents

Abstract

The invention relates to a multilayer (1) plastics container for containing a liquid. The wall (2) of the container (1) includes, from the inside to the outside of said container (1): a first polyethylene layer (10) having on the inner surface (15) thereof a fluorinated surface (16) obtained by means of fluorination, a second layer (20) that is made of an adhesive material capable of rigidly connecting the first layer (10) and a third layer (30), a third layer (30) that is made of polymer and capable of blocking a plurality of solvents and oxygen, a fourth layer (40) that is made of an adhesive material capable of rigidly connecting the third layer (30) and a fifth layer (50), a fifth layer (50) that has a water vapor transmission rate at 40°C and 90% humidity that is less than a threshold R_o no higher than 10.6 g.µm/m²/24h.

Description

 Multilayer plastic container.

The present invention relates to a multilayer plastic container.

 Plastic containers (polymers) are commonly used for the packaging of liquids, including consumable liquids, cosmetics, hygiene products. These containers may also be intended to contain liquids consisting wholly or partly of solvents. The plastic containers are, in the latter case, used in preference to metal containers especially for reasons of weight gain and impact resistance.

 But some plastics, used for the manufacture of walls of these containers, do not have sufficient impermeability to solvents. In this case, when the liquid comprises one or more solvents, there is a migration of these solvents in the wall towards the outside of the container, which causes in particular a deformation of the container.

 Certain plastics used for the manufacture of walls of these containers, in particular polyolefins, also have the disadvantage of allowing the flavors and / or flavors of certain liquids contained in the container to migrate into the wall of the container. This phenomenon of migration (in English "scalping") is undesirable because it denatures the liquid and makes it less pleasant for consumption or use. On the other hand, some of the plastics used for the walls do not constitute a barrier to oxygen either, or the absorption of oxygen through the walls can also cause a deformation of the containers. Some of the plastics used also have insufficient impermeability to humidity (as water vapor in the atmosphere).

 There is therefore a need for a container which has none of the disadvantages mentioned above.

The invention aims to provide a multilayer plastic container capable of containing a liquid that is impermeable to solvents, oxygen and moisture. This object is achieved by the fact that the wall of the container comprises, from the inside to the outside of the container:

 a first layer which is the inner layer of the container, which is made of polyethylene and which has on its inner face a fluorinated surface obtained by fluorination,

 a second layer which is made of an adhesive material capable of joining the first layer and a third layer,

 a third layer which is made of polymer and capable of barrier to a plurality of solvents and to oxygen,

a fourth layer which is made of adhesive material capable of joining the third layer and a fifth layer,

a fifth layer which is the outer layer of the container and which has a transmission rate of water vapor at 40 ° C. and 90% humidity which is below a threshold Ro less than or equal to 10.6 g / m 2; / m ² / 24Hrs.

 Thanks to these provisions, the solvents, flavors and flavors of liquids contained in the container are preserved because the liquid compounds responsible for these aromas and flavors do not penetrate through the fluorinated surface. The fluorinated surface further contributes to preventing contamination of the liquid contained in the container by the wall of the container. The third layer gives the wall of the container an additional impermeability to aromas and solvents, and also to oxygen. The fifth layer gives the wall of the container impermeability to moisture.

 The invention also relates to a method of manufacturing a container adapted to contain a liquid.

 According to the invention, this method comprises the following steps:

(a) A parison comprising a plurality of layers, including a first layer which is the inner layer of the container and which is made of polyethylene, is coextruded, a second layer which is made of an adhesive material capable of joining the first layer and a third layer, a third layer which is made of polymer and which is capable of barrier to a plurality of solvents and oxygen, a fourth layer which is made of adhesive material capable of joining the third layer and a fifth layer, a fifth layer which is the outer layer of the container and which has a water vapor transmission rate of 40 ° C and 90% humidity that is below a Ro threshold of less than or equal to 10.6 gm / m ² / 24Hrs;

 (b) The parison is placed between shells forming a mold defining a space whose shape is that of the container;

(c) the hulls are closed on the parison;

 (d) plate the parison against the hulls;

 (e) fluorination of the inner face of the first layer of the parison so that the first layer has on its inner face a fluorinated surface.

 The invention will be better understood and its advantages will appear better on reading the detailed description which follows, of an embodiment shown by way of non-limiting example. The description refers to the accompanying drawings in which:

 FIG. 1 is a longitudinal section of a container according to the invention, showing the structure of the wall of this container,

FIG. 2 is a schematic representation of the steps of the method according to the invention.

 In the following description, the terms "inner" / "inner" and "outer" / "outer" denote the region inside and outside container, respectively. The terms "internal" and "external" refer to an inward and outward orientation of the container, respectively.

 In the following description, the term "liquids" refers to liquid materials in the phenomenological sense (a material that can not withstand shear stress) and also materials having a certain viscosity (pastes), all of which are capable of taking instantaneous action. or after a certain time the shape of the container that contains them, as opposed to solid materials.

 Figure 1 shows a container 1 according to the invention, in longitudinal section. The container 1 comprises a wall 2 which delimits the volume.

 Figure 1 comprises an enlargement of the wall 2 which illustrates the structure of this wall 2, which consists of a plurality of layers.

The wall 2 of the container 1 comprises a first layer 10 which is the inner layer of the container 1 and which is made of polyethylene, a second layer 20 which is made of adhesive material, a third layer 30 which is made of polymer, a fourth layer 40 who is made of adhesive material, and a fifth layer 50 which is the outer layer of the container 1.

 The first layer 10 is made of a single polyethylene, which facilitates the manufacture of the wall 2. For example, this polyethylene is a high density polyethylene (HDPE).

 Alternatively, the first layer consists of a mixture of several grades of polyethylene.

 The inner face 15 of the first layer 10a is fluorinated so that the first layer 10 has a fluorinated surface 16. In other words, the first layer 10 has on its inner face 15 a fluorinated surface 16 obtained by fluorination .

 The fluorinated surface 16 is formed either by deposition on the surface of the inner surface of fluorine or of one or more fluorinated compounds to form a coating (fluorinated deposit), or by diffusion to a certain depth of fluorine or fluorinated compounds from the inner face 15 so that a surface area of the first layer 10 (this area is the region of the first layer 10 which is closest to its inner face 15) is altered. In general, both a fluoride deposit on the inner face of the first layer 10 and an alteration of a surface area of the first layer 10 occur.

 In all cases, the liquid contained in the container 1 is then in contact with the fluorinated surface 16.

 The fluorinated surface 16 forms a barrier against the migration of components of the liquid contained in the container 1 towards the inside of the wall, since these components can not penetrate the fluorinated surface 16. In addition, the fluorinated surface 16 prevents the migration of components. 2 in particular to the liquid contained in the container 1. In particular, the fluorinated surface 16 acts as a barrier layer for solvents capable of migrating from the liquid contained in the container 1 to the inside of the wall 2.

 Processes for obtaining the fluorinated surface 16 are described below. The first layer 10 has a thickness greater than or equal to 0.26 mm in the finished product.

In fact, depending on the shape of the article to be extruded, if the thickness is less than this value, the tests carried out by the inventors show that there is a risk of creating one or more discontinuities in the layer 10.

 The adhesive material of the second layer 20 is able to secure the first layer 10 and a third layer 30.

 This adhesive is for example the "orevac" grade adhesive (reference

18334) manufactured by ATO.

 The third layer 30 is able to barrier a plurality of solvents and oxygen. Among the solvents to which the third layer 30 is capable of barrier, there is xylene.

 The third layer 30 consists for example of one or more of the following materials: EVOH (polyethylene vinyl alcohol), PVDF (polyvinylidine chloride), polyamide (nylon).

 The adhesive material of the fourth layer 40 is able to join the fifth layer 50 and the third layer 30 together.

The fifth layer 50 has a transmission rate of water vapor at 40 ° C. and 90% humidity which is below a positive threshold Ro and less than or equal to 10.6 g / m ² / 24Hrs (in these units, g denotes a gram, Mm a micron, m is a meter, and Hrs hours)

 Indeed, the material of the third layer 30, which is a barrier to oxygen and solvents, is degraded by water vapor. It is therefore necessary that the wall 2 comprises between the third layer 30 and the outside atmosphere, a barrier that is as effective as possible against water vapor. This barrier is constituted by the fifth layer 50, which constitutes the outer layer of the wall 2, that is to say the layer of the container 1 which is in contact with the atmosphere outside the container 1.

The fifth layer 50 does not include polypropylene. Indeed, polypropylene has a higher water vapor transmission rate than other polymers (the water vapor transmission rate of polypropylene is of the order of 10.7 to 11 g-m / m ² / 24Hrs), which is disadvantageous.

For example, the threshold Ro is less than or equal to 10.5 g / m ² / 24Hrs, or less than or equal to 10.4 g / m ² / 24Hrs, or less than or equal to 10.3 g / m ² / 24Hrs. m / m ² / 24Hrs, or less than or equal to 10.2 g / m ² / 24Hrs, or less than or equal to 10.1 g / m ² / 24Hrs, or less than or equal to 10 g / m / m ² / 24Hrs, or less than or equal to 9.9 gm / m ² / 24Hrs, or less than or equal to 9.8 gm / m ² / 24Hrs, or less than or equal to 9.7g m / m ² / 24Hrs, or lower or equal to 9.6 g / m ² / 24Hr, or less than or equal to 9.5 g / m ² / 24Hr or less than or equal to 9.4 g / m ² / 24Hr, or less or equal to 9.3 gm / m ² / 24Hr, or less than or equal to 9.2 gmm / m ² / 24Hr, or less than or equal to 9.1gm / m ² / 24Hr, or less or equal to 9 gm / m ² / 24Hr, or less than or equal to 8.9 gm / m ² / 24Hr, or less than or equal to 8.8gm / m ² / 24Hr, or less or equal to 8.7 g / m ² / 24Hrs, or less than or equal to 8.6 g / m ² / 24Hrs, or less than or equal to 8.5 g / m ² / 24Hrs or less or equal to 8.4 gm m / m ² / 24Hr, or less than or equal to 8.3 gm / m ² / 24Hr, or less than or equal to 8.2 gmm / m ² / 24Hr, or less or equal to 8.1 gm / m ² / 24Hr, or less than or equal to 8 gm / m ² / 24Hr, or less than or equal to 7.9 gm / m ² / 24Hr, or less or equal to 7.8 gm / m ² / 24Hr, or less than or equal to 7.7 gmm / m ² / 24Hr, or less than or equal to 7.6gmm / m ² / 24Hr, or less or equal to 7.5 g ^ m / m ² / 24Hrs or less than or equal to 7.4 g m ^ / m ² / 24hrs, or less than or equal to 7.3 g-m / m ² / 24hrs, or less than or equal to 7.2 m ^ g / ^m2 / 24Hrs, or less than or equal to 7.1 g / m ² / 24Hr, or less than or equal to 7 g / m ² / 24Hr, or less than or equal to 6.9 g / m ² / 24Hr, or less than or equal to 6.8 gm / m ² / 24Hr, or less than or equal to 6.7 gmm / m ² / 24Hr, or less than or equal to 6.6 gmm / m ² / 24Hr, or less than or equal to 6.5 gm m / m ² / 24Hr or less than or equal to 6.4 gm m / m ² / 24Hr or less than or equal to 6.3 gm / m ² / 24Hr, or less than or equal to 6.2 g / m ² / 24Hr, or less than or equal to 6.1 g / m ² / 24Hr, or less than or equal to 6 g / m ² / 24Hr, or less than or equal to 5.9 gm / m ² / 24Hr, or less than or equal to 5.8 gm / m ² / 24Hr, or less than or equal to 5.7 gmm / m ² / 24Hr, or less than or equal to 5.6 g / m ² / 24Hr, or less than or equal to 5.5 g / m ² / 24Hr or less than or equal to 5.4 g / m ² / 24Hr, or less than or equal to 5.3 g- m / m ² / 24Hr s, or less than or equal to 5.2 m ^ g / m ² / 24hrs, or less than or equal to 5.1 m ^ g / m ² / 24hrs, or less than or equal to 5 m ^ g / ^m2 / 24Hrs , or less than or equal to 4.9 g / m ² / 24Hrs, or less than or equal to 4.8 g / m ² / 24Hrs, or less than or equal to 4.7 g / m ² / m ² / 24Hrs, or less than or equal to 4.6 g ^ m / m ² / 24Hrs, or less than or equal to 4.5 g ^ m / m ² / 24Hrs or less than or equal to 4.4 g ^ m / m ² / 24Hrs, or less than or equal to 4.3 g-m / m ² / 24Hrs, or less than or equal to 4.2 g / m ² / 24Hrs, or less than or equal to 4.1 g / m ² / m ² / 24Hrs, or less than or equal to 4 g / m ² / 24Hrs, or less than or equal to 3.9 g / m ² / 24Hrs, or less than or equal to 3.8 g / m ² / 24Hrs, or less than or equal to 3.7 g ^ m / m ² / 24Hrs, or less or equal to 3.6 gm / m ² / 24Hr, or less than or equal to 3.5 gm / m ² / 24Hr or less than or equal to 3.4 gmm / m ² / 24Hr, or less or equal to 3.3 gm / m ² / 24Hr, or less than or equal to 3.2 gm / m ² / 24Hr, or less than or equal to 3.1gm / m ² / 24Hr, or less or equal to 3 gm / m ² / 24Hr, or less than or equal to 2.9 gm / m ² / 24Hr, or less than or equal to 2.8 gm / m ² / 24Hr, or less or equal to 2.7 gm m / m ² / 24Hr, or less than or equal to 2.6 gm m / m ² / 24Hr, or less than or equal to 2.5 gm / m ² / 24Hr or less or equal to 2.4 gm m / m ² / 24Hr, or less than or equal to 2.3 gm / m ² / 24Hr, or less than or equal to 2.2 gmm / m ² / 24Hr, or less or equal to 2.1 gm / m ² / 24Hr, or less than or equal to 2 gm / m ² / 24Hr, or less than or equal to 1.9gm / m ² / 24Hr, or less or equal to 1.8 g-m / m ² / 24hrs, or less than or equal to 1.7 m ^ g / m ² / 24hrs, or less than or equal to 1.6 m ^ g / m ² / 24hrs or less or equal to 1.5 gm / m ² / 24Hrs or in less than or equal to 1.4 gm m / m ² / 24Hr, or less than or equal to 1.3 gm / m ² / 24Hr, or less than or equal to 1.2 gmm / m ² / 24Hr, or less than or equal to 1.1 gm / m ² / 24Hrs, or less than or equal to 1 gm / m ² / 24Hrs, or less than or equal to 0.9 gm m / m ² / 24Hrs, or less than or equal to 0.8 gm / m ² / 24Hr, or less than or equal to 0.7 gmm / m ² / 24Hr, or less than or equal to 0.6 gmm / m ² / 24Hr, or less than or equal to 0.5 gm / m ² / 24Hr or less than or equal to 0.4 gmm / m ² / 24Hr, or less than or equal to 0.3 gm / m ² / 24Hr, or less than or equal to 0.2 g / m ² / 24Hrs, or less than or equal to 0.1 g / m ² / 24Hrs.

For example, the fifth layer 50 is made of polyethylene. Indeed, the polyethylene has a low water vapor transmission rate, for example equal to 5.9 g / m ² / 24Hrs, as shown by tests carried out by the inventors.

Advantageously, the fifth layer 50 is made of polyethylene whose density is strictly greater than 948 kg / m ³ .

 According to a variant of the invention, the layer 50 consists of a mixture of several distinct grades of polyethylene. By "grade" is meant one or more of the structural properties of polyethylene, such as molecular weight distribution and density.

Indeed, the mechanical properties of the layer 50 can be improved compared to a layer made of polyethylene whose density is lower, as shown by the tests carried out by the inventors. Advantageously, the density of the layer 50 is greater than 953 kg / m ³ .

 The fifth layer 50 consists of a single layer. Alternatively, the fifth layer 50 is constituted by a plurality of sub-layers, each of the sub-layers being different from the sub-layer or layers that are adjacent thereto.

 This structure of the fifth layer 50 in several superposed distinct sub-layers has the advantage of conferring on this outer layer particular properties.

 The different sub-layers are for example made of different materials, or are made of the same material but different by another property (for example the density), resulting from different manufacturing processes.

 The fifth layer 50 may also contain additives such as talc to further enhance its rigidity. The fifth layer 50 may also contain reinforcements such as glass fibers.

 The invention also relates to a method of manufacturing a container 1 as described above. The steps of this process are described below, and are illustrated in FIG.

A parison 80 comprising a plurality of layers, a first layer 10 which is the inner layer of the container 1 and which is made of polyethylene, is coextruded with the aid of an extruder 95, a second layer 20 which is made of suitable adhesive material to secure the first layer 10 and a third layer 30, a third layer 30 which is made of polymer and capable of barrier to a plurality of solvents and oxygen, a fourth layer 40 which is made of adhesive material capable of joining together the third layer 30, and a fifth layer 50 which is the outer layer of the container 1 and which has a transmission rate of water vapor at 40 ° C. and 90% humidity which is less than a threshold Ro less than or equal to at 10.6 g / m ² / 24Hrs (step (a)).

 Alternatively, the threshold Ro is less than one of the values listed above in the description of the container according to the invention.

FIG. 2 shows the channels of the extruder 95, and in each channel is injected (the injection is shown in FIG. 2 by horizontal arrows) the material forming one of the layers of the parison 80. This parison 80 is placed between shells 92 forming a mold 90 (step (b)).

 The shells 92 are closed on the parison 80 (step (c)).

 The mold 90 delimits a space whose shape is that of the container 1 that it is desired to obtain (container 1 in its final form). The mold 90 has an opening 91 which is intended to constitute the opening of the container 1 after the manufacture of this container.

 This parison 80 is pressed against the shells 92 (step (d)).

 For example, this plating is effected by blowing a gas into the space surrounded by the parison 80.

 Alternatively, this plating takes place by making a gap between the parison 80 and the shells 92 of the mold 90.

 Fluorination of the inner face 15 of the first layer 10 of the parison 80 so that the inner face 15 has a fluorinated surface 16 (step (e)).

 For example, this fluorination is carried out as follows:

 This space is injected with a fluorinated gas such that a deposition of fluorine or fluorinated compounds occurs on the internal face 15 of the inner layer (first layer 10) of the parison 90 and / or an alteration of the zone surface of the first layer 10. This alteration occurs by diffusion of fluorine or fluorinated compounds in this superficial zone. This diffusion can be accompanied by a chemical reaction of fluorine or fluorinated compounds with the material of the first layer 10.

The fluorinated gas is for example a mixture of a gas such as nitrogen (N ₂ ) and fluorine (F ₂ ).

 The injection is effected for example by means of a nozzle 93 which is inserted into the opening 91 of the mold 90 so as to open into this space.

 After this injection and after cooling the parison 80, the hulls 92 are then moved aside in order to release the container 1, which is now in its final form, and whose wall 2 is formed by the parison 80.

 Alternatively, the fluorination of the inner face 15 of the first layer 10 of the parison 80 is performed after removing the container 1 of the mold 90, the container 1 then being in its final form.

For example, this fluorination is carried out by injecting a fluorinated gas into the interior space of the container 1. Alternatively, this fluorination is carried out by placing the container 1 in a chamber heated to a temperature above room temperature, and filled with a fluorine-containing gas. This is called "post-fluoridation".

 Advantageously, steps (d) and (e) are simultaneous.

 This alternative embodiment saves time in the manufacturing process of the container 1. This variant is illustrated in FIG.

 Thus, for example, according to this variant, the step (e) of injection of the fluorinated gas is simultaneous with the step (d) of plating of the parison.

 In this case, the fluorinated gas is injected under a pressure sufficient to press the parison 90 against the walls of the hulls 92 of the mold.

Claims

1. A multilayer container (1) of plastics material adapted to contain a liquid, the wall (2) of said container (1) being characterized in that it comprises, from the inside to the outside of said container (1):  - a first layer (10) which is the inner layer of said container (1), which is made of polyethylene and which has on its inner face (15) a fluorinated surface (16) obtained by fluorination,  a second layer (20) made of an adhesive material capable of joining said first layer (10) and a third layer (30), a third layer (30) which is made of polymer and capable of barrier to a plurality of solvents and to oxygen, a fourth layer (40) which is made of adhesive material capable of joining said third layer (30) and a fifth layer (50), a fifth layer (50) which is the outer layer of said container (1) and which presents a transmission rate of water vapor at 40 ° C. and 90% humidity which is below a threshold Ro less than or equal to 10.6 g / m ² / 24Hrs.  2. Container according to claim 1 characterized in that said fifth layer (50) does not contain polypropylene.  3. Container according to claim 1 characterized in that said fifth layer (50) is made of polyethylene. 4. Container according to claim 3 characterized in that the density of said fifth layer (50) is strictly greater than 948 kg / m ³ .  5. Container according to any one of claims 1 to 4, characterized in that said fifth layer (50) consists of a plurality of sub-layers, each of said sub-layers being different from the one or more sub-layers which are adjacent to it.  6. A method of manufacturing a container (1) characterized in that it comprises the following steps: (a) a parison (80) comprising a plurality of layers, including a first layer (10) which is the inner layer of said container (1) and which is made of polyethylene, is coextruded, a second layer (20) which is made of an adhesive material adapted to secure said first layer (10) and a third layer (30), a third layer (30) which is made of polymer and which is capable of barrier to a plurality of solvents and oxygen, a fourth layer (40) which is made of adhesive material capable of joining said third layer (30), and a fifth layer (50), a fifth layer (50) which is the outer layer of said container (1) and which has a water vapor transmission rate at 40 ° C and 90% humidity which is below a Ro threshold of less than or equal to 10.6 gm / m ² / 24Hrs;  (b) placing said parison (80) between shells (92) forming a mold (90) defining a space whose shape is that of said container (1); (c) closing said shells (92) on said parison (80);  (d) plate said parison (80) against said shells (92);  (e) fluorinating the inner face (15) of said first layer (10) of the parison (80) such that said first layer (10) has on its inner face (15) a fluorinated surface (16); ). 7. Process according to claim 6, characterized in that in step (e), a fluorinated gas is injected into said space so as to effect a fluorination of said internal face (15).  8. The method of claim 6 or 7, characterized in that the steps (d) and (e) are simultaneous.