Stock material or miscellaneous articles – Composite – Of epoxy ether
Reexamination Certificate
2000-11-20
2002-11-26
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of epoxy ether
C428S036900, C523S461000, C525S455000, C528S124000
Reexamination Certificate
active
06485834
ABSTRACT:
The present invention concerns a flexible preform which is radially deployable to form a tubular structure which is hardenable following deployment after positioning in a well or conduit to mould to its shape, to constitute a casing which is usually substantially cylindrical.
Preforms are known with walls of flexible material which can be collapsed on itself to give a radial dimension which is much smaller than the diameter of the well or conduit to be cased in the event of local repair of a well or casing. The preform is introduced into the well or conduit in its collapsed state and once it is in the desired position, it is deployed by radial outward deformation, for example by introducing an inflating fluid such as a gas or liquid inside the preform The applied pressure causes it to mould to the shape of the well or conduit. Such preforms normally comprise a thermosetting resin. In general, the resin forms part of the constituting wall of the preform and is very often introduced by impregnating the fibres forming the wall. Hardening the resin by thermosetting may be brought about by the temperature in the well, but normally it is caused either by introducing a hot fluid inside the preform or by a Joule effect using suitable electrical resistors located in the preform, for example electric wires forming part of the frame of the preform wall, impregnated with thermosetting resin. The heat released by an exothermic reaction which is initiated inside the preform can also be used, usually by bringing the reactants into contact at the desired time.
The preform of the present invention can be positioned and anchored without the need for cement. Within the context of the present invention, the term “flexible preform” means any assembly preferably having an integrated heating system which can hold a thermosetting resin in a medium confined between outer and inner skins of elastic material. Preforms of this type are described, for example, in French patent FR-A-2 722 239, and International patents WO-A-94/21887, WO-A-94/18180 and WO-A-94/25655. The contents of these patents are hereby incorporated by reference and are considered to form an integral part of the present description.
Such preforms must comprise a thermosetting resin having particular characteristics. The resin used must confer superior mechanical properties on the preform, in particular when used in wells, especially in oil wells, they must have high resistance to hydrothermal and chemical ageing, they must have as small as possible a water take-up and the highest possible latency, to allow storage and transport of the preform before it is put in position without the polymerisation reaction starting or having advanced too far.
The present invention also concerns thermosetting compositions with improved latency, with a low water take-up, having a glass transition temperature of at least 100° C., preferably at least 120° C. and more preferably at least 140° C., comprising at least one epoxy resin formed from at least one polyepoxide containing at least two epoxy groups in its molecule and at least one aromatic polyamine containing at least two primary amino groups in its molecule and at least one alkanoyl substituent containing 1 to 12 carbon atoms located in the position alpha to one of the amino groups, the molar ratio of the amine to the epoxide being such that each amino group corresponds to 1.6 to 2.6 epoxy groups, the thermosetting compositions of the invention further comprising a flow controller.
The present invention also concerns the use of these compositions for the production of pre-impregnates with high latency in processes demanding intermediate steps of several hours at 80° C. and the use of these compositions as protective coatings in conduits for fluids (liquid, gas or a mixture of liquid and gas), in particular transport conduits for liquid and/or gaseous hydrocarbons. These coatings can be applied to the inside and also to the outside of the conduits. The invention further concerns the use of these compositions as protective coatings for storage facilities. In general terms, the invention concerns the use of these compositions as a protective coating for any metallic or non metallic surface which can come into contact with agents which cause the degradation of a material or the surface of a material when they come into contact with the surface of the material. More precisely, this is the case for any surface which comes into contact with a corrosive atmosphere or with an adsorbable or absorbable product causing swelling of the material. In the case of conduits or storage facilities for hydrocarbons, these coatings, which have a very low water adsorption capacity, can prevent corrosion by water by preventing direct contact between the material and water or humidity contained in the product in contact with the material, which can be earth in the case of buried conduits or facilities, air in the case of above-ground conduits or facilities, or the moisture contained in hydrocarbons. The scope of the invention also includes the use of these compositions in the micro-electronics field and in the electromechanical field, two fields in which a very low water adsorption capacity is an important factor.
The choice of aromatic polyamines used in the present invention is guided in particular by the fact that it is desirable to have access to aromatic polyamines with low reactivity and low solubility at a temperature of less than about 90° C., occasionally less than about 40° C., in the epoxy resins used. The choice is also influenced by the fact that these aromatic polyamines must preferably result in good resistance to hydrolysis by secondary and tertiary amine moieties which it generates by reaction on the epoxide ring. It must also result in good temperature resistance properties.
In its widest form, then, the present invention concerns a radially deployable flexible preform which forms a tubular structure which is hardenable following deployment after positioning in a well or a conduit to mould to its shape, characterized in that it comprises at least one epoxy resin formed from at least one polyepoxide containing at least two epoxy groups in its molecule, and at least one aromatic polyamine containing at least two primary amino groups in its molecule and at least one alkanoyl substituent containing 1 to 12 carbon atoms located in the position alpha to one of the amino groups, the molar ratio of the amine to the epoxide being such that each amino group corresponds to 1.6 to 2.6 epoxy groups.
Processes using aromatic polyamines as hardeners for certain epoxy resins are known in the industry, such as the various types of ARALDITE®, EPIKOTE® resins, EPON® resins, the resin obtained from the diglycidylether of bis-phenol-F (hereinafter abbreviated to DGEBF) and, in particular, the resin obtained from the diglycidylether of bis-phenol-A (hereinafter abbreviated to DGEBA). In these processes, express recommendations are made that the amine be dissolved before impregnation into the reinforcing fibre, for example glass fibre, carbon fibre, ceramic fibre or a natural or synthetic fibre. The skilled person is aware that practically any aromatic polyamine can be used as an epoxy resin hardener. Selection of a limited number of polyamines which could produce the required properties for the preforms of the invention would thus not be obvious.
The epoxy resin can be selected from the group formed by the commercially available resins cited above, the diglycidylether of bis-phenol-A or bis-phenol-F, bis-phenol formol resin, phenol-novolac resin, cycloaliphatic resins, tri- or tetra-functional resins, resins formed from triglycidylether-isocyanurate and/or triglycidylether-cyanurate and/or triglycidyl-cyanurate and/or triglycidyl-isocyanurate, or mixtures of at least two of these resins.
The epoxy resins obtained from the epoxy resins cited in U.S. patent U.S. Pat. No. 4,921,047 can also be used within the context of the present invention. The content of this patent is hereby incorporated by reference and is considered to form
Audigier Dominique
Delhomme Henri
Jacquemin-Hauviller Frederique
Mariaggi Paul
Dawson Robert
Institut Francais du Pe'trole
Keehan Christopher M
Millen White Zelano & Branigan P.C.
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