METHOD FOR PREPARING THE INTERNAL SHELL OF A COMPOSITE TYPE IV RESERVOIR FOR STORING PRESSURIZED FLUID

Abstract

The present invention relates to a method for manufacturing an internal shell of a composite type IV reservoir delimiting an internal cavity intended to accommodate a pressurized fluid and comprising at least one metal baseplate allowing connection between said internal cavity and the outside of the internal shell, said baseplate or baseplates being secured to the internal shell, said method comprising the following steps: a) a step of applying at least one adhesive layer of a first polymer to the part or parts of the metal baseplate or baseplates intended to be in direct contact with the material of which the internal shell is made; b) a step of incorporating said baseplate or baseplates thus coated into a mould the internal cavity of which is of a shape that corresponds to the shape of the internal shell that is to be obtained; c) a step of forming, on the internal wall of the mould and on the part or parts of the baseplate or baseplates intended to be in contact with the material of which the internal shell is made, at least one layer of a second polymer different from said first polymer and adhering to the first polymer, thus forming the aforementioned internal shell equipped with the aforementioned baseplate or baseplates.

Claims

1. Method for manufacturing an internal shell of a composite type IV reservoir delimiting an internal cavity intended to accommodate a pressurized fluid and comprising at least one metal baseplate allowing connection between said internal cavity and the outside of the internal shell, said baseplate or baseplates being secured to the internal shell, said method comprising the following steps: a) a step of applying at least one adhesive layer of a first polymer to the part or parts of the metal baseplate or baseplates intended to be in direct contact with the material of which the internal shell is made; b) a step of incorporating said baseplate or baseplates thus coated into a mould the internal cavity of which has a shape that corresponds to the shape of the internal shell that is to be obtained; c) a step of forming, on the internal wall of the mould and on the part or parts of the baseplate or baseplates intended to be in contact with the material of which the internal shell is made, at least one layer of a second polymer different from said first polymer and adhering to the first polymer, thus forming the aforementioned internal shell equipped with the aforementioned baseplate or baseplates.

2. Method according to claim 1, in which the first polymer comprises groups capable of adhering to a metal surface by the formation of covalent bonds.

3. Method according to claim 2, in which said groups are chosen from among maleic anhydride groups, silane groups, silanol groups, acrylic groups, peroxide groups and combinations of these groups.

4. Method according to claim 3, in which the first polymer is a polymer comprising a main chain comprising a first repetitive unit derived from polymerisation of an ethylenic monomer and comprising a second repetitive unit comprising a pendant chain comprising at least one group capable of adhesion to a metal surface as defined in claim 3.

5. Method according to claim 1, in which the first polymer is a polymer belonging to the polyethylenes family.

6. Method according to claim 3, in which the first polymer is a polymer comprising a repetitive ethylenic unit and a repetitive unit derived from said repetitive ethylenic unit, comprising a pendant chain comprising at least one group capable of adhesion to a metal surface, this group being chosen from among the groups listed in claim 3.

7. Method according to claim 1, in which the deposition steps a) is done using the manual powder sprinkling technique, the electrostatic paint deposition technique or the fluidised bed deposition technique.

8. Method according to claim 1, in which step c) is done by rotational moulding.

9. Method according to claim 1, in which the second polymer is a thermoplastic polymer.

10. Method according to claim 1, in which the second polymer is a polymer in which some of its repetitive units are identical to those of the first polymer.

11. Method according to claim 1, in which the second polymer is a polymer belonging to the polyethylenes family or the polyamides family.

12. Method according to claim 11, in which, when the second polymer is a polymer belonging to the polyethylenes family, it is a linear or ramified polyethylene.

13. Method according to claim 11, in which, when the second polymer is a polymer belonging to the polyamides family, it is a polyamide-11 or a polyamide-12.

14. Method of preparing a composite type IV reservoir including the following steps: a step to implement the method for preparation of an internal shell of a type IV composite reservoir like that defined in claim 1; and a step to deposit a fibrous material on the external surface of the shell thus obtained in the previous step, to form the external skin of the reservoir.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0074] FIG. 1 shows a cross-sectional view of a baseplate that can be used for implementation of the method according to the invention.

[0075] FIG. 2 shows a cross-sectional view of a baseplate like that illustrated in FIG. 1 positioned in a mould that can be used for implementation of the method according to the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

EXAMPLE 1

[0076] This example illustrates the preparation of an internal shell of a pressurised fluid storage reservoir comprising an aluminium baseplate.

[0077] To achieve this, the first step is to cover the part of the baseplate that will be directly in contact with the shell material by manually sprinkling a powder of a grafted polyethylene of the Matrix N211 type (namely a polyethylene in which the grafts comprise maleic anhydride groups). This baseplate resembles that illustrated in the appended FIG. 1.

[0078] More specifically, for this step, the metal baseplate is preheated to a temperature of 160 C. followed by 2 successive passes of the baseplate in a receptacle comprising a powder of the above-mentioned grafted polyethylene, each of these passes being separated by the baseplate being passed into an oven for 3 minutes at 160 C. The baseplate is thus covered by an approximately 0.8 mm thick layer.

[0079] Secondly, the baseplate thus coated is place in a rotational mould, the internal cavity of which is filled with standard polyethylene (in other words polyethylene that only includes the single repetitive ethylene unit) of the Matrix 6402 U type. The mould is then rotated about two orthogonal axes and its temperature is increased to 210 C. (maximum recorded air temperature inside the mould during the fabrication cycle), as a result of which a polyethylene shell fixed to the baseplate is obtained, allowing communication between the internal cavity of the shell and the exterior. The assembly formed by the shell and the baseplate has excellent resistance, in other words there are no decohesion phenomena between the surface of the baseplate and the grafted polyethylene and between the grafted polyethylene and the standard polyethylene.

[0080] Torsion torques exceeding 100 Nm can be applied to this baseplate/internal shell assembly without damaging the connection. Nor is this assembly damaged by a cross-cut through this assembly. Furthermore, no decohesion is observed when pressure cycles are applied to a reservoir including this assembly.

EXAMPLE 2

[0081] This example illustrates the preparation of an internal shell of a pressurised fluid storage reservoir comprising an aluminium baseplate.

[0082] To achieve this, the first step is to cover the part of the baseplate that will be directly in contact with the shell material by manually sprinkling a powder of a grafted polyethylene of the Matrix N211 type (namely a polyethylene in which the grafts comprise maleic anhydride groups).

[0083] More specifically, for this step, the metal baseplate is preheated to a temperature of 160 C. followed by 2 successive passes of the baseplate in a receptacle comprising a powder of the above-mentioned grafted polyethylene, each of these passes being separated by the baseplate being passed into an oven for 3 minutes at 160 C. The baseplate is thus covered by an approximately 0.8 mm thick layer.

[0084] Secondly, the baseplate thus coated is placed in a rotational mould, the internal cavity of which is filled with a Matrix XL400 type cross-linkable polyethylene (namely a polyethylene comprising a peroxide type cross-linking agent that initiates the cross-linking reaction at a temperature equal to approximatively 150 C.). The mould is then rotated, as a result of which a cross-linked polyethylene shell is obtained fixed to the baseplate that enables communication between the internal cavity of the shell and the outside. The assembly formed by the shell and the baseplate has excellent resistance, in other words there are no decohesion phenomena between the surface of the baseplate and the grafted polyethylene and between the grafted polyethylene and the cross-linked polyethylene.

EXAMPLE 3

[0085] This example illustrates the preparation of an internal shell of a pressurised fluid storage reservoir comprising an aluminium baseplate.

[0086] To achieve this, the first step is to cover the part of the baseplate that will be directly in contact with the shell material by manually sprinkling a powder of a grafted polyolefin of the XP 9015 type comprising specific grafts that can increase adhesion and is compatible with polyamides, such as a polyamide-12.

[0087] More specifically, for this step, the metal baseplate is preheated to a temperature of 160 C. followed by 2 successive passes of the baseplate in a receptacle comprising a powder of the above-mentioned grafted polyolefin, each of these passes being separated by the baseplate being passed into an oven for 3 minutes at 160 C. The baseplate is thus covered by an approximately 0.8 mm thick layer.

[0088] The baseplate thus coated is then placed in a rotational mould, the internal cavity of which is filled with a quantity of micronised polyamide-12 powder, for example of the Rilsan or Matrix ARVO950 type adapted to the required thickness. The mould is then rotated and heated to a maximum temperature of 210 C., and is then cooled, as a result of which a polyamide-12 shell is obtained fixed to the baseplate that enables communication between the internal cavity of the shell and the outside. The assembly formed by the shell and the baseplate has excellent resistance, in other words there are no decohesion phenomena between the surface of the baseplate and the XP9015 grafted polymer and between the XP9015 grafted polymer and the polyamide-12.

EXAMPLE 4

[0089] This example illustrates the preparation of an internal shell of a pressurised fluid storage reservoir comprising an aluminium baseplate.

[0090] To achieve this, the first step is to cover the part of the baseplate that will be directly in contact with the shell material by manually sprinkling a powder of a grafted metallocene polyethylene of the Lumicene mPE3671 type.

[0091] More specifically, for this step, the metal baseplate is preheated to a temperature of 160 C. followed by 2 successive passes of the baseplate in a receptacle comprising a powder of the above-mentioned grafted polyethylene, each of these passes being separated by the baseplate being passed into an oven for 3 minutes at 160 C. The baseplate is thus covered by an approximately 0.8 mm thick layer.

[0092] The baseplate thus coated is then placed in a rotational mould, part of the internal cavity of which is filled with a polyamide-11 and is heated to 220 C. The mould is then rotated, as a result of which a polyamide-11 shell fixed to the baseplate is obtained, that enables communication between the internal cavity of the shell and the outside. The assembly formed by the shell and the baseplate has excellent resistance, in other words there are no decohesion phenomena between the surface of the baseplate and the grafted polyethylene and between the grafted polyethylene and the polyamide-11.

COMPARATIVE EXAMPLE 1

[0093] This example illustrates the preparation of an internal shell of a pressurised fluid storage reservoir comprising an aluminium baseplate.

[0094] To achieve this, the first step is to degrease the aluminium baseplate, that is not coated with an adhesive polymer, as is the case in the method according to the invention.

[0095] Secondly, the baseplate is placed in a rotational mould, the internal cavity of which is filled with standard polyethylene (in other words a polyethylene that only includes a single repetitive ethylene unit) of the Matrix 6402 U type. The mould is then rotated about two orthogonal axes and its temperature is increased to 210 C. (maximum recorded air temperature inside the mould during the fabrication cycle), as a result of which a polyethylene shell fixed to the baseplate is obtained, allowing communication between the internal cavity of the shell and the exterior.

[0096] After cooling, decohesion of the metal baseplate with the polymer forming the shell induced by thermal shrinkage of the polymer is observed over an approximately 800 nm length.

[0097] The visual analysis confirms that the two surfaces are completely smooth and that there is no adhesion.