EP2443353A1

EP2443353A1 - Adhesive assembly and assembly and reinforcement methods comprising the use thereof

Info

Publication number: EP2443353A1
Application number: EP10734278A
Authority: EP
Inventors: Jean-Philippe Court; René-Louis GEFFROY
Original assignee: COLD PAD
Current assignee: COLD PAD
Priority date: 2009-06-19
Filing date: 2010-06-18
Publication date: 2012-04-25
Also published as: FR2947018A1; CN102575700B; US20120096926A1; SG177273A1; KR20120046716A; BRPI1016043A2; BRPI1016043B1; FR2947018B1; US8869595B2; CN102575700A; WO2010146321A1; AU2010261607B2; AU2010261607A1

Abstract

The invention relates to an adhesive assembly in particular for assembling a novel element on a structure or further for reinforcing a structure. The adhesive assembly includes a substrate (1), a rigid element (2) placed with an interval relative to the substrate, at least one seal (3) compressed between the substrate and the rigid element and defining a sealed space within said interval, and a hardened adhesive (13) occupying said space. The seal is compressed by the rigid element that is held on the substrate by the hardened adhesive.

Description

GLUE ASSEMBLY AND METHODS OF ASSEMBLY AND REINFORCEMENT HAVING APPLICATION

The present invention relates to techniques for producing bonded assemblies. It finds applications in very diverse fields among which may be mentioned the connection of an element to a substrate, in particular to a substrate on which no attachment element was initially provided, or the reinforcement of structures that need to be made more resistant in order to repair or prevent the appearance of structural defects. [0003] The assembly of a metal element on a metal substrate is often done by welding. This technique requires a large increase in temperature, which propagates due to the thermal conductivity of the metal substrate. It is sometimes banned because of environmental incompatibilities, for example if a flammable environment is close to the assembly area. Its implementation can also be problematic if the structure comprising the substrate has paints or coatings that degrade at high temperature, since the welding of the element then causes the need to redo the paint or coating, which can be long. and expensive. For these reasons, welding techniques pose serious problems on board off-shore platforms or ships or pipes for the transport of hydrocarbons or other flammable substances. They are commonly used but have the disadvantage of requiring a longer or shorter interruption of exploitation and sometimes binding measures to ensure the required level of security. Welding techniques are also very difficult to implement under water or in a tidal zone.

Another solution is to stick the element on the substrate by means of a thermosetting or thermoplastic adhesive. A difficulty is then to ensure that the desired properties of the adhesive are obtained. In general, Suppliers characterize the properties of adhesives when they are used under well-controlled conditions, particularly in terms of temperature, degree of hygrometry, etc. These conditions are not necessarily met in practice, particularly in the case of intervention in the marine environment. In addition, it is extremely difficult to guarantee the durability of the adhesive if the environment is relatively aggressive, which is also unfavorable to interventions in the marine environment.

Reinforcement of a structure is sometimes achieved by applying a reinforcement of metal or composite material on the structure. Nevertheless, there are problems similar to those previously mentioned in the case of bonding an element on a substrate. In the case of a metal-type reinforcement, the latter is bonded to the structure by means of an adhesive, such as a resin. The composite material usually has a resin that acts as an adhesive, and it is difficult to ensure good behavior if it is applied under poorly controlled conditions. The composite material can degrade over time if the environment of the reinforcement is aggressive. It is the same for the adhesive in the context of a metal reinforcement. The reinforcement conferred on the structure is not sustainable.

The present invention aims to remove some of the limitations of the aforementioned techniques and in particular aims to provide a bonded assembly that is reliable and durable even if the medium is potentially aggressive.

[0008] It is thus proposed a bonded assembly, comprising:

a substrate;

a rigid element arranged with an interval relative to the substrate; at least one compressed seal between the substrate and the rigid element and delimiting a sealed volume in said gap; and

a cured adhesive occupying said volume, the gasket being compressed by the rigid element retained on the substrate by the cured adhesive.

The adhesive, contained in the sealed volume between the seal, the substrate and the rigid element, is advantageously isolated from the environment surrounding the bonded assembly. The seal allows this isolation both during the realization of the assembly, so that one can control the implementation conditions and therefore the properties of the adhesive, and during the subsequent use of the assembly which thus has good durability. We can then choose the adhesive depending on the desired properties and be confident in the effective and sustainable achievement of these properties.

In a second aspect, the invention provides a method of assembling a rigid element on a substrate. This process comprises the following steps:

/ a / arranging the rigid element relative to the substrate, at least one permanent seal being placed between the rigid element and the substrate so as to define a volume in a gap between the rigid element and the substrate;

IbI bring the rigid element of the substrate so as to compress the permanent seal and to seal said volume; and / c / curing an adhesive in the sealed volume.

In another application of a bonded assembly according to the invention, there is provided a method of reinforcing a structure comprising the following steps:

/ a / arranging a rigid element facing a substrate that comprises said structure, at least one permanent seal being placed between the rigid element and the substrate so as to delimit a volume in a gap between the rigid element and the substrate ;

IbI bring the rigid element of the substrate so as to compress the permanent seal and to seal said volume; and here curing an adhesive in the sealed volume to form a composite reinforcement insulated from the outside by the permanent seal maintained compressed by the rigid member.

Other features and advantages of the present invention will appear in the following description of nonlimiting exemplary embodiments, with reference to the accompanying drawings, in which: - AT -

- Figure 1 is a schematic view of an embodiment of a bonded assembly according to the invention;

FIGS. 2 to 8 are schematic representations of successive steps of an exemplary method; - Figure 9 is a schematic view of another embodiment of a bonded assembly according to the invention.

In the various figures, the same references denote identical or similar elements.

With reference to FIG. 1, a glued assembly according to the invention comprises a substrate 1 and a rigid element 2 which, in the example shown, is in the form of a plate covering part of the substrate. A permanent seal 3 is compressed between the rigid plate 2 and the substrate 1. The seal 3 delimits, in the gap between the plate 2 and the substrate 1, a volume occupied by a hardened adhesive 13. [0015] A seal of Installation 4 may optionally be placed between the plate 2 and the substrate 1, around the permanent joint 3. This installation joint 4 is more flexible than the permanent joint 3. Its role will be explained later.

The hardened adhesive 13 maintains the spacing between the rigid element 2 and the substrate 1, so that the rigid element 2 permanently applies a compressive force on the gasket 3. The gasket 3 thus compressed ensures sealing against the external environment of the volume occupied by the adhesive 13, which protects it from the aggressiveness that can present the external environment. By "rigid element" 2 is meant a plate-shaped element or other element whose rigidity is sufficient to transmit to the peripheral seal 3 a compressive force when this element 2 is biased in its central region towards the substrate 1. contact surface between the hardened adhesive 13 and the gasket 3 also contributes to the maintenance of the gasket 3.

The rigid element 2 is typically made of metal, composite material or any other material having sufficient rigidity and adequate hold in the environment where the assembly will be used. Gasket permanent 3 is made of a material, such as an elastomer, chosen for its resistance in this environment. For example, in marine environment, it is possible to use for the seal 3 an elastomer EPDM type or Viton ®.

In one embodiment, the bonded assembly may comprise one or more sensors 7-9 located in the gap between the rigid element 2 and the substrate 1. Such sensors make it possible to detect physical parameters in this interval. , For example :

the temperature which can in particular be measured by a thermocouple 8;

the humidity level that can be measured by a humidity probe 7; and

the deformation which can be measured by a strain gauge 9 preferably disposed on the substrate 1.

The measurement signals from the sensor 7-9 or 7-9 are conveyed out of the assembly bonded by links 14 which pass through the rigid plate 2 in a connection beam 10 sealingly integrated with the plate 2. These signals can thus be exploited to evaluate mainly the conditions of installation of the bonded assembly but also the aging conditions of the hardened adhesive 13, ensure its good behavior over time and determine a possible need to repair the assembly .

In particular, the tightness of the volume occupied by the hardened adhesive 13 between the substrate 1 and the plate 2 is a property that it may be desirable to check over time. To this end, a hygrometry sensor 7 may be placed in contact with a hydrophilic element 6 placed to capture moisture that may penetrate the volume occupied by the cured adhesive 13. In the embodiment shown in FIG. Figure 1, the hydrophilic element 6 is inserted into an annular groove that has the permanent seal 3, to capture moisture tending to penetrate along the substrate 1 to the adhesive.

The adhesive used is typically a thermosetting resin, for example of EPONAL ® or ARALDITE ® type. Fibers and / or reinforcing fillers may be added to its composition. The presence of fibers in the hardened adhesive 13 makes it possible to increase its resistance to mechanical stresses.

If the adhesive is injected into the volume defined by the seal in the gap between the substrate 1 and the plate 2, the fibers coated by the adhesive may be short fibers mixed with the injected adhesive. The directions of orientation of the short fibers are then random in the hardened adhesive 13, which gives the latter substantially isotropic mechanical properties.

The fibers may also be long fibers of a mat or fiber fabric placed between the substrate 1 and the plate 2 during installation. The use of long fibers makes it possible to orient them in one or more major directions if the application made of the assembly requires a greater resistance of the hardened adhesive 13 according to such directions.

In another embodiment, long fibers may be placed in the gap between the substrate 1 and the plate 2 by using a prepreg, that is to say a set of fibers embedded in a resin maintained at low temperature to delay setting. When laying the plate 2, the prepreg is placed in the interval and then the resin hardens during the rise in temperature.

The permanent joint 3 plays an important role when the bonded assembly is used after being laid. Compressed by the rigid plate 2, it protects the adhesive 13 from the outside environment, which provides better conditions of durability.

The role of the seal 3 is also important during the installation of the assembly. During this installation, the rigid plate 2 is biased towards the substrate 1, either by means of a vacuum in the volume defined by the seal, or by the application of a force to the back of the plate 2. This stress compresses the seal 3 thus sealing the volume that will occupy the cured adhesive. The sealed volume makes it possible to achieve physical conditions, particularly in terms of temperature, pressure and hygrometry, suitable for the implementation of the adhesive. This implementation can thus take place in the manner recommended by the supplier of the adhesive. This gives the desired performance of the assembly, even if it is performed in a difficult environment such as marine environment.

A method of installing a bonded assembly according to the invention is illustrated in FIGS. 2 to 8. In this example, it is a question of assembling a rigid element 2 in the form of a plate on a substrate 1. In order to allow mounting of other elements on the substrate, the plate 2 may be equipped with connection systems such as clevises, anchor bars, bolts or threads, etc., not shown in the drawings. The substrate 1 may be metallic, for example a part of the deck or the hull of a ship or an off-shore platform.

In a first step (optional) illustrated in Figure 2, the substrate is cleaned in the area 20 which will be covered by the rigid plate 2, by means of solvents and / or abrasives. It is then possible to present the plate 2 on which the permanent joint 3 and the installation joint 4 have been positioned (FIG. 3). The seals 3, 4 extend along the periphery of the plate 2, the installation joint 4 being more flexible than the permanent joint 3 and placed outside thereof. The installation joint 4 may be perpendicular to the plate 2 a greater thickness than the permanent joint 3 to come first in contact with the substrate 1. If sensors and / or a hydrophilic element 6 (not shown in FIGS. 8) must be installed in the gap between the substrate 1 and the rigid plate 2, they can be put in place by being pre-installed on the plate 2 presented facing the substrate 1.

Once the contact is made, a pumping system 22 is activated to put the gap between the substrate 1 and the plate 2 in depression through a pipe 23 provided in the plate 2 inside the permanent joint 3 ( Figure 4). The depression urges the plate 2 towards the substrate 1 and compresses the seals 3, 4. In the initial phase of pumping, it may be that the stiffness of the permanent seal 3 does not allow it to achieve a good seal given the Asperities that may present the substrate 1. The installation gasket 4, compressed first provides this initial seal. When the vacuum becomes sufficient, the permanent seal is also crushed between the substrate 1 and the plate 2 and provides the desired seal. Then, a second conduit 24 which is provided with the plate 2 is used to introduce processing fluids in the volume sealed by the seal 3 and maintained in depression by the conduit (Figure 5). In the example shown, the duct 24 is connected to two other ducts 25, 27 which can selectively be opened or closed by respective valves 26, 28. In the phase represented by FIG. 5, the duct 25 is put into communication, by opening the valve 26, with one or more reservoirs 29 containing the desired treatment fluids while the valve 28 is closed. The fluids which are thus circulated in the sealed volume and collected by the duct 23 maintained in depression can comprise:

- Solvents or primers intended to prepare the surfaces facing the substrate 1 and the plate 2 and the inner side of the permanent seal 3 to facilitate the adhesion of the adhesive to be subsequently injected. Suitable solvents or primers will generally be indicated by the supplier of the adhesive used;

- Dry air at controlled temperature, intended to achieve in the sealed volume the desired temperature and humidity conditions.

When the desired conditions have been achieved in the sealed volume, one can begin the injection of the adhesive in the liquid state 15, optionally containing short reinforcing fibers. In the example illustrated in FIG. 6, the injection is carried out by putting the conduit 27 in an adhesive reservoir 30 in the liquid state 15 and opening the valve 28, the valve 26 being closed. The liquid adhesive 15 propagates in the sealed volume. Once this volume is completely filled (FIG. 7), the liquid adhesive leaves via the conduit 23. It can be detected in this conduit 23 or in a buffer tank 31 of the pumping system 22. Following this detection, the valve 28 is closed then the ducts 23, 24 are closed on the back of the plate 2 at the locations marked 33, 34 in Figure 7.

The closed sealed volume is then completely occupied by the liquid adhesive 15. The resin constituting the adhesive 15 is polymerized, maintaining it for the time prescribed by the resin supplier. It may be appropriate to heat the plate to accelerate the crosslinking. This heating can be made by contact on the back of the plate 2, being observed that the crosslinking temperatures, typically a few tens of degrees, are much lower than those achieved during the implementation of a welding process. Once polymerized, the adhesive 13 maintains the permanent seal 3 by adhesion and compression, generated during installation, between the substrate 1 and the rigid element 2 (Figure 8).

The glued assembly can be used temporarily if it is suitable for the application. It can be dismounted by sawing the adhesive 13 and the joints 3, 4 with an abrasive wire. An example of using a temporary bonded assembly is in the temporary assembly of a guide for laying a module on an off-shore oil platform.

The shape of the rigid element 2 may be adapted to the shape of the substrate 1. The bonded assembly may in particular be installed in an angle of a structure or on curved surfaces. The shape of the rigid element 2 can also be adapted to contribute optimally to the structural reinforcement of the substrate 1.

Another application of a bonded assembly according to the invention is the strengthening of a structure, either as a preventive measure, the structure having to withstand stronger loads than initially expected, or as a repair of a cracked zone, corroded or perforated.

For structural reinforcement, the rigid element 2 and the adhesive 13 can be put in place in the same manner as that described with reference to FIGS. 2 to 8. In general, reinforcement elements will be coated by the adhesive between the substrate 1 and the rigid element 2 to increase the strength properties.

The reinforcing elements will preferably be fibers.

As in the previous example, it may be short fibers, the amount of which will be calculated according to the efforts to be taken up by the system bonded to the substrate 1. They may also be longer fibers belonging to the a mattress or fabric placed in the gap when presenting the rigid element 2.

The long fibers are arranged in a manner dependent on the repair or reinforcement to be performed. For example, if it is a question of repairing a substrate 1 having a crack 40 (FIG. 9), a rather large proportion of the fibers will be arranged transversely to the direction of the crack.

In the example illustrated in Figure 9, the reinforcing fibers belong to a prepreg 50 placed between the substrate 1 and the rigid element 2 during the realization of the assembly. The prepreg 50, refrigerated before being put in place to retard the crosslinking of the resin that it incorporates, can consist, in a manner known per se, in a stack of layers comprising, for example:

an adhesive film 51 on the side of the substrate 1; - The actual pre-impregnated pad 52, that is to say the assembly of fibers embedded in a resin whose setting is retarded by the cold;

a weft of fibers 55 which may be invaded by the resin during the compression of the prepreg; an adhesive film 56 on the side of the rigid element 2.

It will be understood that very diverse arrangements of the prepreg, other than that illustrated in Figure 9, are used in the context of the present invention. For example, the prepreg may further comprise a heating blanket for heating the resin when it is necessary to ensure its crosslinking, and an intermediate film. These additional elements can then be arranged to maintain a continuity of the adhesive between the substrate 1 and the rigid element 2.

For the installation of the bonded assembly illustrated in Figure 9, the depression is made, through the conduit 23, in the volume defined by the permanent seal 3 and the installation seal 4. As before, we make circulate dry air in the sealed volume to control the conditions hygrometric and temperature. It is possible to complete the depression via the conduit 23 by pressing the rigid element 2 to compress the prepreg. When the resin of the prepreg reflux through the conduit 23, it is closed and the resin is crosslinked in the sealed volume, if necessary by heating. If the resin of the prepreg is not sufficient to fill the volume after solicitation of the rigid plate 2 to the substrate 1, it is possible to carry out a complementary injection in the manner indicated with reference to FIGS. 6 and 7.

We see in Figure 9 a permanent joint 3 and an installation gasket 4 of different shapes from those shown in Figures 1 to 8. The permanent joint 3 has an M profile whose side is glued to the plate 2 and the other side is pressed against the substrate 1. The installation gasket 4 is a flexible sheet bonded to the central portion of the M profile of the permanent seal 3 and applied to the substrate 1 around the rigid plate 2. If necessary, wedge wedges may be inserted into the triangular groove formed at the periphery of the M 3 gasket to control the thickness of the gap between the substrate. 1 and the rigid plate 2 during the implementation. The control of the thickness of the gap between the substrate 1 and the rigid plate 2 also makes it possible to better control the geometry and thus the behavior of the composite reinforcement. In the case of Figure 1, the permanent seal 3 has a trapezoidal profile while the installation seal 4 is bellows-shaped. In the case of FIGS. 2 to 8, the permanent joint 3 has a round profile and the installation joint 4 is in the form of a skirt surrounding the permanent joint 3. In general, it will be understood that the permanent joint 3 and, when it is present, the installation joint 4 can have very varied forms within the scope of the invention.

The applications of the bonded assembly according to the invention are very varied. We can for example quote:

- connections for support of a new element on a marine or maritime installation, particularly oil;

- connections for support of a new element to be placed under water, for example on or under the hull of an FPSO platform (floating production, storage and offloading) or in the tidal zone or in compartments such as ballast tanks;

- the temporary connections of the laying guides on an offshore installation, where epoxy, polyurethane, polyester, vinylester, methacrylate, silicone and polyimide glues are used as adhesive for their known qualities in terms of resilience and resistance;

- reinforcements of structures (beams: soles and webs, poles, bracons, sheets, etc.) - repair of a damaged structural zone, for example by corrosion;

- Repair of a perforated structural zone where the seal is to be reconstituted. The rigid elements to be bonded can be placed on both sides of the zone-substrate to be treated; - repair of a cracked area;

- repair of a pipeline, including underwater, to restore its watertightness or resistance;

- repair, reinforcement or connection in civil engineering works, industrial production, etc. - repair, reinforcement or connection on ships, aircraft ...

Claims

1. Glued assembly, comprising:

a substrate (1);

- a rigid element (2) disposed with an interval relative to the substrate; at least one seal (3) compressed between the substrate and the rigid element and delimiting a sealed volume in said gap; and

a hardened adhesive (13) occupying said volume, the gasket being compressed by the rigid element retained on the substrate by the hardened adhesive.

The bonded assembly of claim 1, wherein an adherent interface is formed between the cured adhesive and the compressed seal.

A bonded assembly according to any one of the preceding claims, wherein fillers are coated by the cured adhesive (13) in said volume.

4. Bonded assembly according to any one of the preceding claims, comprising at least one sensor (7-9) located in the gap between the rigid element (2) and the substrate (1), for detecting at least one physical parameter. in said interval.

5. Bonded assembly according to claim 4, wherein the sensor comprises a humidity sensor (7), the assembly further comprising a hydrophilic element (6) located at the seal (3) and in contact with the sensor. humidity.

6. A method of assembling a rigid element on a substrate, the method comprising the following steps:

/ a / arranging the rigid element (2) with respect to the substrate (1), at least one permanent seal (3) being placed between the rigid element and the substrate of delimiting a volume in a gap between the rigid member and the substrate;

IbI bring the rigid element of the substrate so as to compress the permanent seal and to seal said volume; and Id curing an adhesive (15) in the sealed volume.

7. A method of reinforcing a structure comprising at least one substrate (1), the method comprising the following steps:

/ a / arranging a rigid element (2) facing the substrate, at least one permanent seal (3) being placed between the rigid element and the substrate so as to delimit a volume in a gap between the rigid element and the substrate ;

IbI bring the rigid element of the substrate so as to compress the permanent seal and to seal said volume; and

Here, curing an adhesive (15) in the sealed volume to form a composite reinforcement insulated from the outside by the permanent seal maintained compressed by the rigid element.

8. The method of claim 6 or 7, comprising a preliminary step of surface treatment of the substrate (1) by abrasion and / or application of solvents.

9. Method according to any one of claims 6 to 8, wherein the approximation of the rigid element (2) relative to the substrate (1) comprises a depression of the defined volume in the interval between the rigid element. and the substrate.

10. The method of claim 9, wherein a plant gasket (4) softer than the permanent seal (3) is placed between the rigid element (2) and the substrate (1) near the permanent joint.

11. Method according to any one of claims 6 to 10, wherein the approximation of the rigid element (2) relative to the substrate (1) comprises the application of a force on the rigid element to the substrate.

12. Method according to any one of claims 6 to 11, wherein, between the steps IbI and Ici, is circulated in the sealed volume a dry gas and / or at least one solvent and / or at least one product of primer.

13. A method according to any one of claims 6 to 12, wherein the adhesive (15) is injected in the liquid state into the sealed volume before curing.

The method according to claim 13, wherein short reinforcing fibers are dispersed in the adhesive (15) injected in the liquid state.

The method of any one of claims 6 to 12, wherein at least a portion of the adhesive is part of a prepreg (50) positioned in the gap between the rigid member (2) and the substrate (1).

16. The method of claim 15, wherein the approximation of the rigid element (2) relative to the substrate (1) is carried out at least until discharge of the adhesive of the prepreg through a conduit (23) of which is provided with the rigid element.